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Rust编写的JavaScript引擎，该项目是一个试验性质的项目。
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boa/boa/src/builtins/string/mod.rs

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//! This module implements the global `String` object.
//!
//! The `String` global object is a constructor for strings or a sequence of characters.
//!
//! More information:
//! - [ECMAScript reference][spec]
//! - [MDN documentation][mdn]
//!
//! [spec]: https://tc39.es/ecma262/#sec-string-object
//! [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String
pub mod string_iterator;
#[cfg(test)]
mod tests;
use crate::builtins::Symbol;
use crate::object::{JsObject, PROTOTYPE};
use crate::{
builtins::{string::string_iterator::StringIterator, Array, BuiltIn, RegExp},
object::{ConstructorBuilder, ObjectData},
property::{Attribute, PropertyDescriptor},
symbol::WellKnownSymbols,
BoaProfiler, Context, JsResult, JsString, JsValue,
};
use std::{
char::{decode_utf16, from_u32},
cmp::{max, min},
string::String as StdString,
};
use unicode_normalization::UnicodeNormalization;
pub(crate) fn code_point_at(string: JsString, position: i32) -> Option<(u32, u8, bool)> {
let size = string.encode_utf16().count() as i32;
if position < 0 || position >= size {
return None;
}
let mut encoded = string.encode_utf16();
let first = encoded.nth(position as usize)?;
if !is_leading_surrogate(first) && !is_trailing_surrogate(first) {
return Some((first as u32, 1, false));
}
if is_trailing_surrogate(first) || position + 1 == size {
return Some((first as u32, 1, true));
}
let second = encoded.next()?;
if !is_trailing_surrogate(second) {
return Some((first as u32, 1, true));
}
let cp = (first as u32 - 0xD800) * 0x400 + (second as u32 - 0xDC00) + 0x10000;
Some((cp, 2, false))
}
/// Helper function to check if a `char` is trimmable.
#[inline]
pub(crate) fn is_trimmable_whitespace(c: char) -> bool {
// The rust implementation of `trim` does not regard the same characters whitespace as ecma standard does
//
// Rust uses \p{White_Space} by default, which also includes:
// `\u{0085}' (next line)
// And does not include:
// '\u{FEFF}' (zero width non-breaking space)
// Explicit whitespace: https://tc39.es/ecma262/#sec-white-space
matches!(
c,
'\u{0009}' | '\u{000B}' | '\u{000C}' | '\u{0020}' | '\u{00A0}' | '\u{FEFF}' |
// Unicode Space_Separator category
'\u{1680}' | '\u{2000}'
..='\u{200A}' | '\u{202F}' | '\u{205F}' | '\u{3000}' |
// Line terminators: https://tc39.es/ecma262/#sec-line-terminators
'\u{000A}' | '\u{000D}' | '\u{2028}' | '\u{2029}'
)
}
pub(crate) fn is_leading_surrogate(value: u16) -> bool {
(0xD800..=0xDBFF).contains(&value)
}
pub(crate) fn is_trailing_surrogate(value: u16) -> bool {
(0xDC00..=0xDFFF).contains(&value)
}
/// JavaScript `String` implementation.
#[derive(Debug, Clone, Copy)]
pub(crate) struct String;
impl BuiltIn for String {
const NAME: &'static str = "String";
fn attribute() -> Attribute {
Attribute::WRITABLE | Attribute::NON_ENUMERABLE | Attribute::CONFIGURABLE
}
fn init(context: &mut Context) -> (&'static str, JsValue, Attribute) {
let _timer = BoaProfiler::global().start_event(Self::NAME, "init");
let symbol_iterator = WellKnownSymbols::iterator();
let attribute = Attribute::READONLY | Attribute::NON_ENUMERABLE | Attribute::PERMANENT;
let string_object = ConstructorBuilder::with_standard_object(
context,
Self::constructor,
context.standard_objects().string_object().clone(),
)
.name(Self::NAME)
.length(Self::LENGTH)
.property("length", 0, attribute)
.method(Self::char_at, "charAt", 1)
.method(Self::char_code_at, "charCodeAt", 1)
.method(Self::code_point_at, "codePointAt", 1)
.method(Self::to_string, "toString", 0)
.method(Self::concat, "concat", 1)
.method(Self::repeat, "repeat", 1)
.method(Self::slice, "slice", 2)
.method(Self::starts_with, "startsWith", 1)
.method(Self::ends_with, "endsWith", 1)
.method(Self::includes, "includes", 1)
.method(Self::index_of, "indexOf", 1)
.method(Self::last_index_of, "lastIndexOf", 1)
.method(Self::r#match, "match", 1)
.method(Self::normalize, "normalize", 1)
.method(Self::pad_end, "padEnd", 1)
.method(Self::pad_start, "padStart", 1)
.method(Self::trim, "trim", 0)
.method(Self::trim_start, "trimStart", 0)
.method(Self::trim_end, "trimEnd", 0)
.method(Self::to_lowercase, "toLowerCase", 0)
.method(Self::to_uppercase, "toUpperCase", 0)
.method(Self::substring, "substring", 2)
.method(Self::substr, "substr", 2)
.method(Self::split, "split", 2)
.method(Self::value_of, "valueOf", 0)
.method(Self::match_all, "matchAll", 1)
.method(Self::replace, "replace", 2)
.method(Self::replace_all, "replaceAll", 2)
.method(Self::iterator, (symbol_iterator, "[Symbol.iterator]"), 0)
.method(Self::search, "search", 1)
.method(Self::at, "at", 1)
.build();
(Self::NAME, string_object.into(), Self::attribute())
}
}
impl String {
/// The amount of arguments this function object takes.
pub(crate) const LENGTH: usize = 1;
/// JavaScript strings must be between `0` and less than positive `Infinity` and cannot be a negative number.
/// The range of allowed values can be described like this: `[0, +∞)`.
///
/// The resulting string can also not be larger than the maximum string size,
/// which can differ in JavaScript engines. In Boa it is `2^32 - 1`
pub(crate) const MAX_STRING_LENGTH: f64 = u32::MAX as f64;
/// `String( value )`
///
/// <https://tc39.es/ecma262/#sec-string-constructor-string-value>
pub(crate) fn constructor(
new_target: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// This value is used by console.log and other routines to match Object type
// to its Javascript Identifier (global constructor method name)
let string = match args.get(0) {
Some(value) if value.is_symbol() && new_target.is_undefined() => {
Symbol::to_string(value, &[], context)?
.as_string()
.expect("'Symbol::to_string' returns 'Value::String'")
.clone()
}
Some(value) => value.to_string(context)?,
None => JsString::default(),
};
if new_target.is_undefined() {
return Ok(string.into());
}
// todo: extract `GetPrototypeFromConstructor` function
let prototype = new_target
.as_object()
.and_then(|obj| {
obj.__get__(&PROTOTYPE.into(), obj.clone().into(), context)
.map(|o| o.as_object())
.transpose()
})
.transpose()?
.unwrap_or_else(|| context.standard_objects().object_object().prototype());
Ok(Self::string_create(string, prototype, context).into())
}
/// Abstract function `StringCreate( value, prototype )`.
///
/// Call this function if you want to create a `String` exotic object.
///
/// More information:
/// - [ECMAScript reference][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-stringcreate
fn string_create(value: JsString, prototype: JsObject, context: &mut Context) -> JsObject {
// 7. Let length be the number of code unit elements in value.
let len = value.encode_utf16().count();
// 1. Let S be ! MakeBasicObject(« [[Prototype]], [[Extensible]], [[StringData]] »).
// 2. Set S.[[Prototype]] to prototype.
// 3. Set S.[[StringData]] to value.
// 4. Set S.[[GetOwnProperty]] as specified in 10.4.3.1.
// 5. Set S.[[DefineOwnProperty]] as specified in 10.4.3.2.
// 6. Set S.[[OwnPropertyKeys]] as specified in 10.4.3.3.
let s = context.construct_object();
s.set_prototype_instance(prototype.into());
s.borrow_mut().data = ObjectData::string(value);
// 8. Perform ! DefinePropertyOrThrow(S, "length", PropertyDescriptor { [[Value]]: 𝔽(length),
// [[Writable]]: false, [[Enumerable]]: false, [[Configurable]]: false }).
s.define_property_or_throw(
"length",
PropertyDescriptor::builder()
.value(len)
.writable(false)
.enumerable(false)
.configurable(false),
context,
)
.expect("length definition for a new string must not fail");
// 9. Return S.
s
}
fn this_string_value(this: &JsValue, context: &mut Context) -> JsResult<JsString> {
match this {
JsValue::String(ref string) => return Ok(string.clone()),
JsValue::Object(ref object) => {
let object = object.borrow();
if let Some(string) = object.as_string() {
return Ok(string);
}
}
_ => {}
}
Err(context.construct_type_error("'this' is not a string"))
}
/// Get the string value to a primitive string
#[allow(clippy::wrong_self_convention)]
#[inline]
pub(crate) fn to_string(
this: &JsValue,
_: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// Get String from String Object and send it back as a new value
Ok(JsValue::new(Self::this_string_value(this, context)?))
}
/// `String.prototype.charAt( index )`
///
/// The `String` object's `charAt()` method returns a new string consisting of the single UTF-16 code unit located at the specified offset into the string.
///
/// Characters in a string are indexed from left to right. The index of the first character is `0`,
/// and the index of the last character—in a string called `stringName`—is `stringName.length - 1`.
/// If the `index` you supply is out of this range, JavaScript returns an empty string.
///
/// If no index is provided to `charAt()`, the default is `0`.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.charat
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/charAt
pub(crate) fn char_at(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let primitive_val = this.to_string(context)?;
let pos = args
.get(0)
.cloned()
.unwrap_or_else(JsValue::undefined)
.to_integer(context)? as i32;
// Fast path returning empty string when pos is obviously out of range
if pos < 0 || pos >= primitive_val.len() as i32 {
return Ok("".into());
}
// Calling .len() on a string would give the wrong result, as they are bytes not the number of
// unicode code points
// Note that this is an O(N) operation (because UTF-8 is complex) while getting the number of
// bytes is an O(1) operation.
if let Some(utf16_val) = primitive_val.encode_utf16().nth(pos as usize) {
Ok(JsValue::new(from_u32(utf16_val as u32).unwrap()))
} else {
Ok("".into())
}
}
/// `String.prototype.at ( index )`
///
/// This String object's at() method returns a String consisting of the single UTF-16 code unit located at the specified position.
/// Returns undefined if the given index cannot be found.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/proposal-relative-indexing-method/#sec-string.prototype.at
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/at
pub(crate) fn at(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
let this = this.require_object_coercible(context)?;
let s = this.to_string(context)?;
let len = s.encode_utf16().count();
let relative_index = args
.get(0)
.cloned()
.unwrap_or_default()
.to_integer(context)?;
let k = if relative_index < 0 as f64 {
len - (-relative_index as usize)
} else {
relative_index as usize
};
if let Some(utf16_val) = s.encode_utf16().nth(k) {
Ok(JsValue::new(
from_u32(u32::from(utf16_val)).expect("invalid utf-16 character"),
))
} else {
Ok(JsValue::undefined())
}
}
/// `String.prototype.codePointAt( index )`
///
/// The `codePointAt()` method returns an integer between `0` to `1114111` (`0x10FFFF`) representing the UTF-16 code unit at the given index.
///
/// If no UTF-16 surrogate pair begins at the index, the code point at the index is returned.
///
/// `codePointAt()` returns `undefined` if the given index is less than `0`, or if it is equal to or greater than the `length` of the string.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.codepointat
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/codePointAt
pub(crate) fn code_point_at(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let primitive_val = this.to_string(context)?;
let pos = args
.get(0)
.cloned()
.unwrap_or_else(JsValue::undefined)
.to_integer(context)? as i32;
// Fast path returning undefined when pos is obviously out of range
if pos < 0 || pos >= primitive_val.len() as i32 {
return Ok(JsValue::undefined());
}
if let Some((code_point, _, _)) = code_point_at(primitive_val, pos) {
Ok(JsValue::new(code_point))
} else {
Ok(JsValue::undefined())
}
}
/// `String.prototype.charCodeAt( index )`
///
/// The `charCodeAt()` method returns an integer between `0` and `65535` representing the UTF-16 code unit at the given index.
///
/// Unicode code points range from `0` to `1114111` (`0x10FFFF`). The first 128 Unicode code points are a direct match of the ASCII character encoding.
///
/// `charCodeAt()` returns `NaN` if the given index is less than `0`, or if it is equal to or greater than the `length` of the string.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.charcodeat
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/charCodeAt
pub(crate) fn char_code_at(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let primitive_val = this.to_string(context)?;
let pos = args
.get(0)
.cloned()
.unwrap_or_else(JsValue::undefined)
.to_integer(context)? as i32;
// Fast path returning NaN when pos is obviously out of range
if pos < 0 || pos >= primitive_val.len() as i32 {
return Ok(JsValue::nan());
}
// Calling .len() on a string would give the wrong result, as they are bytes not the number of unicode code points
// Note that this is an O(N) operation (because UTF-8 is complex) while getting the number of bytes is an O(1) operation.
// If there is no element at that index, the result is NaN
if let Some(utf16_val) = primitive_val.encode_utf16().nth(pos as usize) {
Ok(JsValue::new(f64::from(utf16_val)))
} else {
Ok(JsValue::nan())
}
}
/// `String.prototype.concat( str1[, ...strN] )`
///
/// The `concat()` method concatenates the string arguments to the calling string and returns a new string.
///
/// Changes to the original string or the returned string don't affect the other.
///
/// If the arguments are not of the type string, they are converted to string values before concatenating.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.concat
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/concat
pub(crate) fn concat(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
let object = this.require_object_coercible(context)?;
let mut string = object.to_string(context)?.to_string();
for arg in args {
string.push_str(&arg.to_string(context)?);
}
Ok(JsValue::new(string))
}
/// `String.prototype.repeat( count )`
///
/// The `repeat()` method constructs and returns a new string which contains the specified number of
/// copies of the string on which it was called, concatenated together.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.repeat
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat
pub(crate) fn repeat(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
let object = this.require_object_coercible(context)?;
let string = object.to_string(context)?;
if let Some(arg) = args.get(0) {
let n = arg.to_integer(context)?;
if n < 0.0 {
return context.throw_range_error("repeat count cannot be a negative number");
}
if n.is_infinite() {
return context.throw_range_error("repeat count cannot be infinity");
}
if n * (string.len() as f64) > Self::MAX_STRING_LENGTH {
return context
.throw_range_error("repeat count must not overflow maximum string length");
}
Ok(string.repeat(n as usize).into())
} else {
Ok("".into())
}
}
/// `String.prototype.slice( beginIndex [, endIndex] )`
///
/// The `slice()` method extracts a section of a string and returns it as a new string, without modifying the original string.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.slice
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/slice
pub(crate) fn slice(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let primitive_val = this.to_string(context)?;
// Calling .len() on a string would give the wrong result, as they are bytes not the number of unicode code points
// Note that this is an O(N) operation (because UTF-8 is complex) while getting the number of bytes is an O(1) operation.
let length = primitive_val.chars().count() as i32;
let start = args
.get(0)
.cloned()
.unwrap_or_else(JsValue::undefined)
.to_integer(context)? as i32;
let end = args
.get(1)
.cloned()
.unwrap_or_else(|| JsValue::new(length))
.to_integer(context)? as i32;
let from = if start < 0 {
max(length.wrapping_add(start), 0)
} else {
min(start, length)
};
let to = if end < 0 {
max(length.wrapping_add(end), 0)
} else {
min(end, length)
};
let span = max(to.wrapping_sub(from), 0);
let new_str: StdString = primitive_val
.chars()
.skip(from as usize)
.take(span as usize)
.collect();
Ok(JsValue::new(new_str))
}
/// `String.prototype.startWith( searchString[, position] )`
///
/// The `startsWith()` method determines whether a string begins with the characters of a specified string, returning `true` or `false` as appropriate.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.startswith
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith
pub(crate) fn starts_with(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let primitive_val = this.to_string(context)?;
let arg = args.get(0).cloned().unwrap_or_else(JsValue::undefined);
if Self::is_regexp_object(&arg) {
context.throw_type_error(
"First argument to String.prototype.startsWith must not be a regular expression",
)?;
}
let search_string = arg.to_string(context)?;
let length = primitive_val.chars().count() as i32;
let search_length = search_string.chars().count() as i32;
// If less than 2 args specified, position is 'undefined', defaults to 0
let position = if args.len() < 2 {
0
} else {
args.get(1)
.expect("failed to get arg")
.to_integer(context)? as i32
};
let start = min(max(position, 0), length);
let end = start.wrapping_add(search_length);
if end > length {
Ok(JsValue::new(false))
} else {
// Only use the part of the string from "start"
let this_string: StdString = primitive_val.chars().skip(start as usize).collect();
Ok(JsValue::new(
this_string.starts_with(search_string.as_str()),
))
}
}
/// `String.prototype.endsWith( searchString[, length] )`
///
/// The `endsWith()` method determines whether a string ends with the characters of a specified string, returning `true` or `false` as appropriate.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.endswith
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith
pub(crate) fn ends_with(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let primitive_val = this.to_string(context)?;
let arg = args.get(0).cloned().unwrap_or_else(JsValue::undefined);
if Self::is_regexp_object(&arg) {
context.throw_type_error(
"First argument to String.prototype.endsWith must not be a regular expression",
)?;
}
let search_string = arg.to_string(context)?;
let length = primitive_val.chars().count() as i32;
let search_length = search_string.chars().count() as i32;
// If less than 2 args specified, end_position is 'undefined', defaults to
// length of this
let end_position = if args.len() < 2 {
length
} else {
args.get(1)
.expect("Could not get argument")
.to_integer(context)? as i32
};
let end = min(max(end_position, 0), length);
let start = end.wrapping_sub(search_length);
if start < 0 {
Ok(JsValue::new(false))
} else {
// Only use the part of the string up to "end"
let this_string: StdString = primitive_val.chars().take(end as usize).collect();
Ok(JsValue::new(this_string.ends_with(search_string.as_str())))
}
}
/// `String.prototype.includes( searchString[, position] )`
///
/// The `includes()` method determines whether one string may be found within another string, returning `true` or `false` as appropriate.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.includes
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes
pub(crate) fn includes(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let primitive_val = this.to_string(context)?;
let arg = args.get(0).cloned().unwrap_or_else(JsValue::undefined);
if Self::is_regexp_object(&arg) {
context.throw_type_error(
"First argument to String.prototype.includes must not be a regular expression",
)?;
}
let search_string = arg.to_string(context)?;
let length = primitive_val.chars().count() as i32;
// If less than 2 args specified, position is 'undefined', defaults to 0
let position = if args.len() < 2 {
0
} else {
args.get(1)
.expect("Could not get argument")
.to_integer(context)? as i32
};
let start = min(max(position, 0), length);
// Take the string from "this" and use only the part of it after "start"
let this_string: StdString = primitive_val.chars().skip(start as usize).collect();
Ok(JsValue::new(this_string.contains(search_string.as_str())))
}
fn is_regexp_object(value: &JsValue) -> bool {
match value {
JsValue::Object(ref obj) => obj.borrow().is_regexp(),
_ => false,
}
}
/// `String.prototype.replace( regexp|substr, newSubstr|function )`
///
/// The `replace()` method returns a new string with some or all matches of a `pattern` replaced by a `replacement`.
///
/// The `pattern` can be a string or a `RegExp`, and the `replacement` can be a string or a function to be called for each match.
/// If `pattern` is a string, only the first occurrence will be replaced.
///
/// The original string is left unchanged.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.replace
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace
pub(crate) fn replace(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// 1. Let O be ? RequireObjectCoercible(this value).
this.require_object_coercible(context)?;
let search_value = args.get(0).cloned().unwrap_or_default();
let replace_value = args.get(1).cloned().unwrap_or_default();
// 2. If searchValue is neither undefined nor null, then
if !search_value.is_null_or_undefined() {
// a. Let replacer be ? GetMethod(searchValue, @@replace).
let replacer = search_value
.as_object()
.unwrap_or_default()
.get_method(context, WellKnownSymbols::replace())?;
// b. If replacer is not undefined, then
if let Some(replacer) = replacer {
// i. Return ? Call(replacer, searchValue, « O, replaceValue »).
return context.call(
&replacer.into(),
&search_value,
&[this.clone(), replace_value],
);
}
}
// 3. Let string be ? ToString(O).
let this_str = this.to_string(context)?;
// 4. Let searchString be ? ToString(searchValue).
let search_str = search_value.to_string(context)?;
// 5. Let functionalReplace be IsCallable(replaceValue).
let functional_replace = replace_value.is_function();
// 6. If functionalReplace is false, then
// a. Set replaceValue to ? ToString(replaceValue).
// 7. Let searchLength be the length of searchString.
let search_length = search_str.len();
// 8. Let position be ! StringIndexOf(string, searchString, 0).
// 9. If position is -1, return string.
let position = if let Some(p) = this_str.index_of(&search_str, 0) {
p
} else {
return Ok(this_str.into());
};
// 10. Let preserved be the substring of string from 0 to position.
let preserved = StdString::from_utf16_lossy(
&this_str.encode_utf16().take(position).collect::<Vec<u16>>(),
);
// 11. If functionalReplace is true, then
// 12. Else,
let replacement = if functional_replace {
// a. Let replacement be ? ToString(? Call(replaceValue, undefined, « searchString, 𝔽(position), string »)).
context
.call(
&replace_value,
&JsValue::undefined(),
&[search_str.into(), position.into(), this_str.clone().into()],
)?
.to_string(context)?
} else {
// a. Assert: Type(replaceValue) is String.
// b. Let captures be a new empty List.
let captures = Vec::new();
// c. Let replacement be ! GetSubstitution(searchString, string, position, captures, undefined, replaceValue).
get_substitution(
search_str.to_string(),
this_str.to_string(),
position,
captures,
JsValue::undefined(),
replace_value.to_string(context)?,
context,
)?
};
// 13. Return the string-concatenation of preserved, replacement, and the substring of string from position + searchLength.
Ok(format!(
"{}{}{}",
preserved,
replacement,
StdString::from_utf16_lossy(
&this_str
.encode_utf16()
.skip(position + search_length)
.collect::<Vec<u16>>()
)
)
.into())
}
/// `22.1.3.18 String.prototype.replaceAll ( searchValue, replaceValue )`
///
/// The replaceAll() method returns a new string with all matches of a pattern replaced by a replacement.
///
/// The pattern can be a string or a RegExp, and the replacement can be a string or a function to be called for each match.
///
/// The original string is left unchanged.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.replaceall
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace
pub(crate) fn replace_all(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// 1. Let O be ? RequireObjectCoercible(this value).
let o = this.require_object_coercible(context)?;
let search_value = args.get(0).cloned().unwrap_or_default();
let replace_value = args.get(1).cloned().unwrap_or_default();
// 2. If searchValue is neither undefined nor null, then
if !search_value.is_null_or_undefined() {
// a. Let isRegExp be ? IsRegExp(searchValue).
if let Some(obj) = search_value.as_object() {
// b. If isRegExp is true, then
if obj.is_regexp() {
// i. Let flags be ? Get(searchValue, "flags").
let flags = obj.get("flags", context)?;
// ii. Perform ? RequireObjectCoercible(flags).
flags.require_object_coercible(context)?;
// iii. If ? ToString(flags) does not contain "g", throw a TypeError exception.
if !flags.to_string(context)?.contains('g') {
return context.throw_type_error(
"String.prototype.replaceAll called with a non-global RegExp argument",
);
}
}
}
// c. Let replacer be ? GetMethod(searchValue, @@replace).
let replacer = search_value
.as_object()
.unwrap_or_default()
.get_method(context, WellKnownSymbols::replace())?;
// d. If replacer is not undefined, then
if let Some(replacer) = replacer {
// i. Return ? Call(replacer, searchValue, « O, replaceValue »).
return replacer.call(&search_value, &[o.into(), replace_value], context);
}
}
// 3. Let string be ? ToString(O).
let string = o.to_string(context)?;
// 4. Let searchString be ? ToString(searchValue).
let search_string = search_value.to_string(context)?;
// 5. Let functionalReplace be IsCallable(replaceValue).
let functional_replace = replace_value.is_function();
// 6. If functionalReplace is false, then
let replace_value_string = if !functional_replace {
// a. Set replaceValue to ? ToString(replaceValue).
replace_value.to_string(context)?
} else {
JsString::new("")
};
// 7. Let searchLength be the length of searchString.
let search_length = search_string.encode_utf16().count();
// 8. Let advanceBy be max(1, searchLength).
let advance_by = max(1, search_length);
// 9. Let matchPositions be a new empty List.
let mut match_positions = Vec::new();
// 10. Let position be ! StringIndexOf(string, searchString, 0).
let mut position = string.index_of(&search_string, 0);
// 11. Repeat, while position is not -1,
while let Some(p) = position {
// a. Append position to the end of matchPositions.
match_positions.push(p);
// b. Set position to ! StringIndexOf(string, searchString, position + advanceBy).
position = string.index_of(&search_string, p + advance_by);
}
// 12. Let endOfLastMatch be 0.
let mut end_of_last_match = 0;
// 13. Let result be the empty String.
let mut result = JsString::new("");
// 14. For each element p of matchPositions, do
for p in match_positions {
// a. Let preserved be the substring of string from endOfLastMatch to p.
let preserved = StdString::from_utf16_lossy(
&string
.clone()
.encode_utf16()
.skip(end_of_last_match)
.take(p - end_of_last_match)
.collect::<Vec<u16>>(),
);
// b. If functionalReplace is true, then
// c. Else,
let replacement = if functional_replace {
// i. Let replacement be ? ToString(? Call(replaceValue, undefined, « searchString, 𝔽(p), string »)).
context
.call(
&replace_value,
&JsValue::undefined(),
&[
search_string.clone().into(),
p.into(),
string.clone().into(),
],
)?
.to_string(context)?
} else {
// i. Assert: Type(replaceValue) is String.
// ii. Let captures be a new empty List.
// iii. Let replacement be ! GetSubstitution(searchString, string, p, captures, undefined, replaceValue).
get_substitution(
search_string.to_string(),
string.to_string(),
p,
Vec::new(),
JsValue::undefined(),
replace_value_string.clone(),
context,
)
.expect("GetSubstitution should never fail here.")
};
// d. Set result to the string-concatenation of result, preserved, and replacement.
result = JsString::new(format!("{}{}{}", result.as_str(), &preserved, &replacement));
// e. Set endOfLastMatch to p + searchLength.
end_of_last_match = p + search_length;
}
// 15. If endOfLastMatch < the length of string, then
if end_of_last_match < string.encode_utf16().count() {
// a. Set result to the string-concatenation of result and the substring of string from endOfLastMatch.
result = JsString::new(format!(
"{}{}",
result.as_str(),
&StdString::from_utf16_lossy(
&string
.encode_utf16()
.skip(end_of_last_match)
.collect::<Vec<u16>>()
)
));
}
// 16. Return result.
Ok(result.into())
}
/// `String.prototype.indexOf( searchValue[, fromIndex] )`
///
/// The `indexOf()` method returns the index within the calling `String` object of the first occurrence
/// of the specified value, starting the search at `fromIndex`.
///
/// Returns `-1` if the value is not found.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.indexof
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf
pub(crate) fn index_of(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
let this = this.require_object_coercible(context)?;
let string = this.to_string(context)?;
let search_string = args
.get(0)
.cloned()
.unwrap_or_else(JsValue::undefined)
.to_string(context)?;
let length = string.chars().count();
let start = args
.get(1)
.map(|position| position.to_integer(context))
.transpose()?
.map_or(0, |position| position.max(0.0).min(length as f64) as usize);
if search_string.is_empty() {
return Ok(start.min(length).into());
}
if start < length {
if let Some(position) = string.find(search_string.as_str()) {
return Ok(string[..position].chars().count().into());
}
}
Ok(JsValue::new(-1))
}
/// `String.prototype.lastIndexOf( searchValue[, fromIndex] )`
///
/// The `lastIndexOf()` method returns the index within the calling `String` object of the last occurrence
/// of the specified value, searching backwards from `fromIndex`.
///
/// Returns `-1` if the value is not found.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.lastindexof
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/lastIndexOf
pub(crate) fn last_index_of(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
let this = this.require_object_coercible(context)?;
let string = this.to_string(context)?;
let search_string = args
.get(0)
.cloned()
.unwrap_or_else(JsValue::undefined)
.to_string(context)?;
let length = string.chars().count();
let start = args
.get(1)
.map(|position| position.to_integer(context))
.transpose()?
.map_or(0, |position| position.max(0.0).min(length as f64) as usize);
if search_string.is_empty() {
return Ok(start.min(length).into());
}
if start < length {
if let Some(position) = string.rfind(search_string.as_str()) {
return Ok(string[..position].chars().count().into());
}
}
Ok(JsValue::new(-1))
}
/// `String.prototype.match( regexp )`
///
/// The `match()` method retrieves the result of matching a **string** against a [`regular expression`][regex].
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.match
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/match
/// [regex]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions
pub(crate) fn r#match(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// 1. Let O be ? RequireObjectCoercible(this value).
let o = this.require_object_coercible(context)?;
// 2. If regexp is neither undefined nor null, then
let regexp = args.get(0).cloned().unwrap_or_default();
if !regexp.is_null_or_undefined() {
// a. Let matcher be ? GetMethod(regexp, @@match).
// b. If matcher is not undefined, then
if let Some(obj) = regexp.as_object() {
if let Some(matcher) = obj.get_method(context, WellKnownSymbols::match_())? {
// i. Return ? Call(matcher, regexp, « O »).
return matcher.call(&regexp, &[o.clone()], context);
}
}
}
// 3. Let S be ? ToString(O).
let s = o.to_string(context)?;
// 4. Let rx be ? RegExpCreate(regexp, undefined).
let rx = RegExp::create(regexp, JsValue::undefined(), context)?;
// 5. Return ? Invoke(rx, @@match, « S »).
let obj = rx.as_object().expect("RegExpCreate must return Object");
if let Some(matcher) = obj.get_method(context, WellKnownSymbols::match_())? {
matcher.call(&rx, &[JsValue::new(s)], context)
} else {
context.throw_type_error("RegExp[Symbol.match] is undefined")
}
}
/// Abstract method `StringPad`.
///
/// Performs the actual string padding for padStart/End.
/// <https://tc39.es/ecma262/#sec-stringpad/>
fn string_pad(
primitive: JsString,
max_length: i32,
fill_string: Option<JsString>,
at_start: bool,
) -> JsValue {
let primitive_length = primitive.len() as i32;
if max_length <= primitive_length {
return JsValue::new(primitive);
}
let filler = fill_string.as_deref().unwrap_or(" ");
if filler.is_empty() {
return JsValue::new(primitive);
}
let fill_len = max_length.wrapping_sub(primitive_length);
let mut fill_str = StdString::new();
while fill_str.len() < fill_len as usize {
fill_str.push_str(filler);
}
// Cut to size max_length
let concat_fill_str: StdString = fill_str.chars().take(fill_len as usize).collect();
if at_start {
JsValue::new(format!("{}{}", concat_fill_str, &primitive))
} else {
JsValue::new(format!("{}{}", primitive, &concat_fill_str))
}
}
/// `String.prototype.padEnd( targetLength[, padString] )`
///
/// The `padEnd()` method pads the current string with a given string (repeated, if needed) so that the resulting string reaches a given length.
///
/// The padding is applied from the end of the current string.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.padend
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padEnd
pub(crate) fn pad_end(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
let primitive = this.to_string(context)?;
if args.is_empty() {
return Err(JsValue::new("padEnd requires maxLength argument"));
}
let max_length = args
.get(0)
.expect("failed to get argument for String method")
.to_integer(context)? as i32;
let fill_string = args.get(1).map(|arg| arg.to_string(context)).transpose()?;
Ok(Self::string_pad(primitive, max_length, fill_string, false))
}
/// `String.prototype.padStart( targetLength [, padString] )`
///
/// The `padStart()` method pads the current string with another string (multiple times, if needed) until the resulting string reaches the given length.
///
/// The padding is applied from the start of the current string.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.padstart
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padStart
pub(crate) fn pad_start(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
let primitive = this.to_string(context)?;
if args.is_empty() {
return Err(JsValue::new("padStart requires maxLength argument"));
}
let max_length = args
.get(0)
.expect("failed to get argument for String method")
.to_integer(context)? as i32;
let fill_string = args.get(1).map(|arg| arg.to_string(context)).transpose()?;
Ok(Self::string_pad(primitive, max_length, fill_string, true))
}
/// String.prototype.trim()
///
/// The `trim()` method removes whitespace from both ends of a string.
///
/// Whitespace in this context is all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator characters (LF, CR, etc.).
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.trim
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trim
pub(crate) fn trim(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
let this = this.require_object_coercible(context)?;
let string = this.to_string(context)?;
Ok(JsValue::new(string.trim_matches(is_trimmable_whitespace)))
}
/// `String.prototype.trimStart()`
///
/// The `trimStart()` method removes whitespace from the beginning of a string.
///
/// Whitespace in this context is all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator characters (LF, CR, etc.).
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.trimstart
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trimStart
pub(crate) fn trim_start(
this: &JsValue,
_: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
let string = this.to_string(context)?;
Ok(JsValue::new(
string.trim_start_matches(is_trimmable_whitespace),
))
}
/// String.prototype.trimEnd()
///
/// The `trimEnd()` method removes whitespace from the end of a string.
///
/// Whitespace in this context is all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator characters (LF, CR, etc.).
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.trimend
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trimEnd
pub(crate) fn trim_end(
this: &JsValue,
_: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
let this = this.require_object_coercible(context)?;
let string = this.to_string(context)?;
Ok(JsValue::new(
string.trim_end_matches(is_trimmable_whitespace),
))
}
/// `String.prototype.toLowerCase()`
///
/// The `toLowerCase()` method returns the calling string value converted to lower case.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.tolowercase
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toLowerCase
#[allow(clippy::wrong_self_convention)]
pub(crate) fn to_lowercase(
this: &JsValue,
_: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let this_str = this.to_string(context)?;
// The Rust String is mapped to uppercase using the builtin .to_lowercase().
// There might be corner cases where it does not behave exactly like Javascript expects
Ok(JsValue::new(this_str.to_lowercase()))
}
/// `String.prototype.toUpperCase()`
///
/// The `toUpperCase()` method returns the calling string value converted to uppercase.
///
/// The value will be **converted** to a string if it isn't one
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.toUppercase
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toUpperCase
#[allow(clippy::wrong_self_convention)]
pub(crate) fn to_uppercase(
this: &JsValue,
_: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let this_str = this.to_string(context)?;
// The Rust String is mapped to uppercase using the builtin .to_uppercase().
// There might be corner cases where it does not behave exactly like Javascript expects
Ok(JsValue::new(this_str.to_uppercase()))
}
/// `String.prototype.substring( indexStart[, indexEnd] )`
///
/// The `substring()` method returns the part of the `string` between the start and end indexes, or to the end of the string.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.substring
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substring
pub(crate) fn substring(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let primitive_val = this.to_string(context)?;
// If no args are specified, start is 'undefined', defaults to 0
let start = if args.is_empty() {
0
} else {
args.get(0)
.expect("failed to get argument for String method")
.to_integer(context)? as i32
};
let length = primitive_val.encode_utf16().count() as i32;
// If less than 2 args specified, end is the length of the this object converted to a String
let end = if args.len() < 2 {
length
} else {
args.get(1)
.expect("Could not get argument")
.to_integer(context)? as i32
};
// Both start and end args replaced by 0 if they were negative
// or by the length of the String if they were greater
let final_start = min(max(start, 0), length);
let final_end = min(max(end, 0), length);
// Start and end are swapped if start is greater than end
let from = min(final_start, final_end) as usize;
let to = max(final_start, final_end) as usize;
// Extract the part of the string contained between the start index and the end index
// where start is guaranteed to be smaller or equals to end
let extracted_string: Result<StdString, _> = decode_utf16(
primitive_val
.encode_utf16()
.skip(from)
.take(to.wrapping_sub(from)),
)
.collect();
Ok(JsValue::new(extracted_string.expect("Invalid string")))
}
/// `String.prototype.substr( start[, length] )`
///
/// The `substr()` method returns a portion of the string, starting at the specified index and extending for a given number of characters afterward.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.substr
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substr
/// <https://tc39.es/ecma262/#sec-string.prototype.substr>
pub(crate) fn substr(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// First we get it the actual string a private field stored on the object only the context has access to.
// Then we convert it into a Rust String by wrapping it in from_value
let primitive_val = this.to_string(context)?;
// If no args are specified, start is 'undefined', defaults to 0
let mut start = if args.is_empty() {
0
} else {
args.get(0)
.expect("failed to get argument for String method")
.to_integer(context)? as i32
};
let length = primitive_val.chars().count() as i32;
// If less than 2 args specified, end is +infinity, the maximum number value.
// Using i32::max_value() should be safe because the final length used is at most
// the number of code units from start to the end of the string,
// which should always be smaller or equals to both +infinity and i32::max_value
let end = if args.len() < 2 {
i32::MAX
} else {
args.get(1)
.expect("Could not get argument")
.to_integer(context)? as i32
};
// If start is negative it become the number of code units from the end of the string
if start < 0 {
start = max(length.wrapping_add(start), 0);
}
// length replaced by 0 if it was negative
// or by the number of code units from start to the end of the string if it was greater
let result_length = min(max(end, 0), length.wrapping_sub(start));
// If length is negative we return an empty string
// otherwise we extract the part of the string from start and is length code units long
if result_length <= 0 {
Ok(JsValue::new(""))
} else {
let extracted_string: StdString = primitive_val
.chars()
.skip(start as usize)
.take(result_length as usize)
.collect();
Ok(JsValue::new(extracted_string))
}
}
/// `String.prototype.split ( separator, limit )`
///
/// The split() method divides a String into an ordered list of substrings, puts these substrings into an array, and returns the array.
/// The division is done by searching for a pattern; where the pattern is provided as the first parameter in the method's call.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.split
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split
pub(crate) fn split(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// 1. Let O be ? RequireObjectCoercible(this value).
let this = this.require_object_coercible(context)?;
let separator = args.get(0).cloned().unwrap_or_default();
let limit = args.get(1).cloned().unwrap_or_default();
// 2. If separator is neither undefined nor null, then
if !separator.is_null_or_undefined() {
// a. Let splitter be ? GetMethod(separator, @@split).
// b. If splitter is not undefined, then
if let Some(splitter) = separator
.as_object()
.unwrap_or_default()
.get_method(context, WellKnownSymbols::split())?
{
// i. Return ? Call(splitter, separator, « O, limit »).
return splitter.call(&separator, &[this.clone(), limit], context);
}
}
// 3. Let S be ? ToString(O).
let this_str = this.to_string(context)?;
// 4. Let A be ! ArrayCreate(0).
let a = Array::array_create(0, None, context)?;
// 5. Let lengthA be 0.
let mut length_a = 0;
// 6. If limit is undefined, let lim be 2^32 - 1; else let lim be ℝ(? ToUint32(limit)).
let lim = if limit.is_undefined() {
u32::MAX
} else {
limit.to_u32(context)?
};
// 7. Let R be ? ToString(separator).
let separator_str = separator.to_string(context)?;
// 8. If lim = 0, return A.
if lim == 0 {
return Ok(a.into());
}
// 9. If separator is undefined, then
if separator.is_undefined() {
// a. Perform ! CreateDataPropertyOrThrow(A, "0", S).
a.create_data_property_or_throw(0, this_str, context)
.unwrap();
// b. Return A.
return Ok(a.into());
}
// 10. Let s be the length of S.
let this_str_length = this_str.encode_utf16().count();
// 11. If s = 0, then
if this_str_length == 0 {
// a. If R is not the empty String, then
if !separator_str.is_empty() {
// i. Perform ! CreateDataPropertyOrThrow(A, "0", S).
a.create_data_property_or_throw(0, this_str, context)
.unwrap();
}
// b. Return A.
return Ok(a.into());
}
// 12. Let p be 0.
// 13. Let q be p.
let mut p = 0;
let mut q = p;
// 14. Repeat, while q ≠ s,
while q != this_str_length {
// a. Let e be SplitMatch(S, q, R).
let e = split_match(&this_str, q, &separator_str);
match e {
// b. If e is not-matched, set q to q + 1.
None => q += 1,
// c. Else,
Some(e) => {
// i. Assert: e is a non-negative integer ≤ s.
// ii. If e = p, set q to q + 1.
// iii. Else,
if e == p {
q += 1;
} else {
// 1. Let T be the substring of S from p to q.
let this_str_substring = StdString::from_utf16_lossy(
&this_str
.encode_utf16()
.skip(p)
.take(q - p)
.collect::<Vec<u16>>(),
);
// 2. Perform ! CreateDataPropertyOrThrow(A, ! ToString(𝔽(lengthA)), T).
a.create_data_property_or_throw(length_a, this_str_substring, context)
.unwrap();
// 3. Set lengthA to lengthA + 1.
length_a += 1;
// 4. If lengthA = lim, return A.
if length_a == lim {
return Ok(a.into());
}
// 5. Set p to e.
p = e;
// 6. Set q to p.
q = p;
}
}
}
}
// 15. Let T be the substring of S from p to s.
let this_str_substring = StdString::from_utf16_lossy(
&this_str
.encode_utf16()
.skip(p)
.take(this_str_length - p)
.collect::<Vec<u16>>(),
);
// 16. Perform ! CreateDataPropertyOrThrow(A, ! ToString(𝔽(lengthA)), T).
a.create_data_property_or_throw(length_a, this_str_substring, context)
.unwrap();
// 17. Return A.
Ok(a.into())
}
/// String.prototype.valueOf()
///
/// The `valueOf()` method returns the primitive value of a `String` object.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.value_of
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/valueOf
pub(crate) fn value_of(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// Use the to_string method because it is specified to do the same thing in this case
Self::to_string(this, args, context)
}
/// `String.prototype.matchAll( regexp )`
///
/// The `matchAll()` method returns an iterator of all results matching a string against a [`regular expression`][regex], including [capturing groups][cg].
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.matchall
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/matchAll
/// [regex]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions
/// [cg]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions/Groups_and_Ranges
pub(crate) fn match_all(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// 1. Let O be ? RequireObjectCoercible(this value).
let o = this.require_object_coercible(context)?;
// 2. If regexp is neither undefined nor null, then
let regexp = args.get(0).cloned().unwrap_or_default();
if !regexp.is_null_or_undefined() {
// a. Let isRegExp be ? IsRegExp(regexp).
// b. If isRegExp is true, then
if regexp.as_object().unwrap_or_default().is_regexp() {
// i. Let flags be ? Get(regexp, "flags").
let flags = regexp.get_field("flags", context)?;
// ii. Perform ? RequireObjectCoercible(flags).
flags.require_object_coercible(context)?;
// iii. If ? ToString(flags) does not contain "g", throw a TypeError exception.
if !flags.to_string(context)?.contains('g') {
return context.throw_type_error(
"String.prototype.matchAll called with a non-global RegExp argument",
);
}
}
// c. Let matcher be ? GetMethod(regexp, @@matchAll).
// d. If matcher is not undefined, then
if let Some(obj) = regexp.as_object() {
if let Some(matcher) = obj.get_method(context, WellKnownSymbols::match_all())? {
// i. Return ? Call(matcher, regexp, « O »).
return matcher.call(&regexp, &[o.clone()], context);
}
}
}
// 3. Let S be ? ToString(O).
let s = o.to_string(context)?;
// 4. Let rx be ? RegExpCreate(regexp, "g").
let rx = RegExp::create(regexp, JsValue::new("g"), context)?;
// 5. Return ? Invoke(rx, @@matchAll, « S »).
let obj = rx.as_object().expect("RegExpCreate must return Object");
if let Some(matcher) = obj.get_method(context, WellKnownSymbols::match_all())? {
matcher.call(&rx, &[JsValue::new(s)], context)
} else {
context.throw_type_error("RegExp[Symbol.matchAll] is undefined")
}
}
/// `String.prototype.normalize( [ form ] )`
///
/// The normalize() method normalizes a string into a form specified in the Unicode® Standard Annex #15
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.normalize
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/normalize
pub(crate) fn normalize(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
let this = this.require_object_coercible(context)?;
let s = this.to_string(context)?;
let form = args.get(0).cloned().unwrap_or_default();
let f_str;
let f = if form.is_undefined() {
"NFC"
} else {
f_str = form.to_string(context)?;
f_str.as_str()
};
match f {
"NFC" => Ok(JsValue::new(s.nfc().collect::<StdString>())),
"NFD" => Ok(JsValue::new(s.nfd().collect::<StdString>())),
"NFKC" => Ok(JsValue::new(s.nfkc().collect::<StdString>())),
"NFKD" => Ok(JsValue::new(s.nfkd().collect::<StdString>())),
_ => context
.throw_range_error("The normalization form should be one of NFC, NFD, NFKC, NFKD."),
}
}
/// `String.prototype.search( regexp )`
///
/// The search() method executes a search for a match between a regular expression and this String object.
///
/// More information:
/// - [ECMAScript reference][spec]
/// - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-string.prototype.search
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/search
pub(crate) fn search(
this: &JsValue,
args: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
// 1. Let O be ? RequireObjectCoercible(this value).
let o = this.require_object_coercible(context)?;
// 2. If regexp is neither undefined nor null, then
let regexp = args.get(0).cloned().unwrap_or_default();
if !regexp.is_null_or_undefined() {
// a. Let searcher be ? GetMethod(regexp, @@search).
// b. If searcher is not undefined, then
if let Some(obj) = regexp.as_object() {
if let Some(searcher) = obj.get_method(context, WellKnownSymbols::search())? {
// i. Return ? Call(searcher, regexp, « O »).
return searcher.call(&regexp, &[o.clone()], context);
}
}
}
// 3. Let string be ? ToString(O).
let string = o.to_string(context)?;
// 4. Let rx be ? RegExpCreate(regexp, undefined).
let rx = RegExp::create(regexp, JsValue::undefined(), context)?;
// 5. Return ? Invoke(rx, @@search, « string »).
let obj = rx.as_object().expect("RegExpCreate must return Object");
if let Some(matcher) = obj.get_method(context, WellKnownSymbols::search())? {
matcher.call(&rx, &[JsValue::new(string)], context)
} else {
context.throw_type_error("RegExp[Symbol.search] is undefined")
}
}
pub(crate) fn iterator(
this: &JsValue,
_: &[JsValue],
context: &mut Context,
) -> JsResult<JsValue> {
StringIterator::create_string_iterator(context, this.clone())
}
}
/// `22.1.3.17.1 GetSubstitution ( matched, str, position, captures, namedCaptures, replacement )`
///
/// More information:
/// - [ECMAScript reference][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-getsubstitution
pub(crate) fn get_substitution(
matched: StdString,
str: StdString,
position: usize,
captures: Vec<JsValue>,
named_captures: JsValue,
replacement: JsString,
context: &mut Context,
) -> JsResult<JsString> {
// 1. Assert: Type(matched) is String.
// 2. Let matchLength be the number of code units in matched.
let match_length = matched.encode_utf16().count();
// 3. Assert: Type(str) is String.
// 4. Let stringLength be the number of code units in str.
let str_length = str.encode_utf16().count();
// 5. Assert: position ≤ stringLength.
// 6. Assert: captures is a possibly empty List of Strings.
// 7. Assert: Type(replacement) is String.
// 8. Let tailPos be position + matchLength.
let tail_pos = position + match_length;
// 9. Let m be the number of elements in captures.
let m = captures.len();
// 10. Let result be the String value derived from replacement by copying code unit elements
// from replacement to result while performing replacements as specified in Table 58.
// These $ replacements are done left-to-right, and, once such a replacement is performed,
// the new replacement text is not subject to further replacements.
let mut result = StdString::new();
let mut chars = replacement.chars().peekable();
while let Some(first) = chars.next() {
if first == '$' {
let second = chars.next();
let second_is_digit = second.map_or(false, |ch| ch.is_digit(10));
// we use peek so that it is still in the iterator if not used
let third = if second_is_digit { chars.peek() } else { None };
let third_is_digit = third.map_or(false, |ch| ch.is_digit(10));
match (second, third) {
// $$
(Some('$'), _) => {
// $
result.push('$');
}
// $&
(Some('&'), _) => {
// matched
result.push_str(&matched);
}
// $`
(Some('`'), _) => {
// The replacement is the substring of str from 0 to position.
result.push_str(&StdString::from_utf16_lossy(
&str.encode_utf16().take(position).collect::<Vec<u16>>(),
));
}
// $'
(Some('\''), _) => {
// If tailPos ≥ stringLength, the replacement is the empty String.
// Otherwise the replacement is the substring of str from tailPos.
if tail_pos < str_length {
result.push_str(&StdString::from_utf16_lossy(
&str.encode_utf16().skip(tail_pos).collect::<Vec<u16>>(),
));
}
}
// $nn
(Some(second), Some(third)) if second_is_digit && third_is_digit => {
// The nnth element of captures, where nn is a two-digit decimal number in the range 01 to 99.
let tens = second.to_digit(10).unwrap() as usize;
let units = third.to_digit(10).unwrap() as usize;
let nn = 10 * tens + units;
// If nn ≤ m and the nnth element of captures is undefined, use the empty String instead.
// If nn is 00 or nn > m, no replacement is done.
if nn == 0 || nn > m {
result.push('$');
result.push(second);
result.push(*third);
} else if let Some(capture) = captures.get(nn - 1) {
if let Some(s) = capture.as_string() {
result.push_str(s);
}
}
chars.next();
}
// $n
(Some(second), _) if second_is_digit => {
// The nth element of captures, where n is a single digit in the range 1 to 9.
let n = second.to_digit(10).unwrap() as usize;
// If n ≤ m and the nth element of captures is undefined, use the empty String instead.
// If n > m, no replacement is done.
if n == 0 || n > m {
result.push('$');
result.push(second);
} else if let Some(capture) = captures.get(n - 1) {
if let Some(s) = capture.as_string() {
result.push_str(s);
}
}
}
// $<
(Some('<'), _) => {
// 1. If namedCaptures is undefined, the replacement text is the String "$<".
// 2. Else,
if named_captures.is_undefined() {
result.push_str("$<")
} else {
// a. Assert: Type(namedCaptures) is Object.
// b. Scan until the next > U+003E (GREATER-THAN SIGN).
let mut group_name = StdString::new();
let mut found = false;
loop {
match chars.next() {
Some('>') => {
found = true;
break;
}
Some(c) => group_name.push(c),
None => break,
}
}
// c. If none is found, the replacement text is the String "$<".
// d. Else,
if !found {
result.push_str("$<");
result.push_str(&group_name);
} else {
// i. Let groupName be the enclosed substring.
// ii. Let capture be ? Get(namedCaptures, groupName).
let capture = named_captures.get_field(group_name, context)?;
// iii. If capture is undefined, replace the text through > with the empty String.
// iv. Otherwise, replace the text through > with ? ToString(capture).
if !capture.is_undefined() {
result.push_str(capture.to_string(context)?.as_str());
}
}
}
}
// $?, ? is none of the above
_ => {
result.push('$');
if let Some(second) = second {
result.push(second);
}
}
}
} else {
result.push(first);
}
}
// 11. Return result.
Ok(result.into())
}
/// `22.1.3.21.1 SplitMatch ( S, q, R )`
///
/// More information:
/// - [ECMAScript reference][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-splitmatch
fn split_match(s_str: &str, q: usize, r_str: &str) -> Option<usize> {
// 1. Let r be the number of code units in R.
let r = r_str.encode_utf16().count();
// 2. Let s be the number of code units in S.
let s = s_str.encode_utf16().count();
// 3. If q + r > s, return not-matched.
if q + r > s {
return None;
}
// 4. If there exists an integer i between 0 (inclusive) and r (exclusive)
// such that the code unit at index q + i within S is different from the code unit at index i within R,
// return not-matched.
for i in 0..r {
if let Some(s_char) = s_str.encode_utf16().nth(q + i) {
if let Some(r_char) = r_str.encode_utf16().nth(i) {
if s_char != r_char {
return None;
}
}
}
}
// 5. Return q + r.
Some(q + r)
}