|
|
|
// 给Number类型增加一个add方法,调用起来更加方便。
|
|
|
|
export function add(num, arg) {
|
|
|
|
return accAdd(arg, num);
|
|
|
|
|
|
|
|
/**
|
|
|
|
** 加法函数,用来得到精确的加法结果
|
|
|
|
** 说明:javascript的加法结果会有误差,在两个浮点数相加的时候会比较明显。这个函数返回较为精确的加法结果。
|
|
|
|
** 调用:accAdd(arg1,arg2)
|
|
|
|
** 返回值:arg1加上arg2的精确结果
|
|
|
|
**/
|
|
|
|
function accAdd(arg1, arg2) {
|
|
|
|
let r1, r2, m, c;
|
|
|
|
try {
|
|
|
|
r1 = arg1.toString().split(".")[1].length;
|
|
|
|
} catch (e) {
|
|
|
|
r1 = 0;
|
|
|
|
}
|
|
|
|
try {
|
|
|
|
r2 = arg2.toString().split(".")[1].length;
|
|
|
|
} catch (e) {
|
|
|
|
r2 = 0;
|
|
|
|
}
|
|
|
|
c = Math.abs(r1 - r2);
|
|
|
|
m = Math.pow(10, Math.max(r1, r2));
|
|
|
|
if (c > 0) {
|
|
|
|
const cm = Math.pow(10, c);
|
|
|
|
if (r1 > r2) {
|
|
|
|
arg1 = Number(arg1.toString().replace(".", ""));
|
|
|
|
arg2 = Number(arg2.toString().replace(".", "")) * cm;
|
|
|
|
} else {
|
|
|
|
arg1 = Number(arg1.toString().replace(".", "")) * cm;
|
|
|
|
arg2 = Number(arg2.toString().replace(".", ""));
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
arg1 = Number(arg1.toString().replace(".", ""));
|
|
|
|
arg2 = Number(arg2.toString().replace(".", ""));
|
|
|
|
}
|
|
|
|
return (arg1 + arg2) / m;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// 给Number类型增加一个sub方法,调用起来更加方便。
|
|
|
|
export function sub(num, arg) {
|
|
|
|
return accSub(num, arg);
|
|
|
|
|
|
|
|
/**
|
|
|
|
** 减法函数,用来得到精确的减法结果
|
|
|
|
** 说明:javascript的减法结果会有误差,在两个浮点数相减的时候会比较明显。这个函数返回较为精确的减法结果。
|
|
|
|
** 调用:accSub(arg1,arg2)
|
|
|
|
** 返回值:arg1加上arg2的精确结果
|
|
|
|
**/
|
|
|
|
function accSub(arg1, arg2) {
|
|
|
|
let r1, r2, m, n;
|
|
|
|
try {
|
|
|
|
r1 = arg1.toString().split(".")[1].length;
|
|
|
|
} catch (e) {
|
|
|
|
r1 = 0;
|
|
|
|
}
|
|
|
|
try {
|
|
|
|
r2 = arg2.toString().split(".")[1].length;
|
|
|
|
} catch (e) {
|
|
|
|
r2 = 0;
|
|
|
|
}
|
|
|
|
m = Math.pow(10, Math.max(r1, r2)); // last modify by deeka //动态控制精度长度
|
|
|
|
n = (r1 >= r2) ? r1 : r2;
|
|
|
|
return ((arg1 * m - arg2 * m) / m).toFixed(n);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// 给Number类型增加一个mul方法,调用起来更加方便。
|
|
|
|
export function mul(num, arg) {
|
|
|
|
return accMul(arg, num);
|
|
|
|
|
|
|
|
/**
|
|
|
|
** 乘法函数,用来得到精确的乘法结果
|
|
|
|
** 说明:javascript的乘法结果会有误差,在两个浮点数相乘的时候会比较明显。这个函数返回较为精确的乘法结果。
|
|
|
|
** 调用:accMul(arg1,arg2)
|
|
|
|
** 返回值:arg1乘以 arg2的精确结果
|
|
|
|
**/
|
|
|
|
function accMul(arg1, arg2) {
|
|
|
|
let m = 0, s1 = arg1.toString(), s2 = arg2.toString();
|
|
|
|
try {
|
|
|
|
m += s1.split(".")[1].length;
|
|
|
|
} catch (e) {
|
|
|
|
}
|
|
|
|
try {
|
|
|
|
m += s2.split(".")[1].length;
|
|
|
|
} catch (e) {
|
|
|
|
}
|
|
|
|
return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// 给Number类型增加一个div方法,调用起来更加方便。
|
|
|
|
export function div(num, arg) {
|
|
|
|
return accDivide(num, arg);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* Return digits length of a number
|
|
|
|
* @param {*number} num Input number
|
|
|
|
*/
|
|
|
|
function digitLength(num) {
|
|
|
|
// Get digit length of e
|
|
|
|
const eSplit = num.toString().split(/[eE]/);
|
|
|
|
const len = (eSplit[0].split(".")[1] || "").length - (+(eSplit[1] || 0));
|
|
|
|
return len > 0 ? len : 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* 把小数转成整数,支持科学计数法。如果是小数则放大成整数
|
|
|
|
* @param {*number} num 输入数
|
|
|
|
*/
|
|
|
|
function float2Fixed(num) {
|
|
|
|
if (num.toString().indexOf("e") === -1) {
|
|
|
|
return Number(num.toString().replace(".", ""));
|
|
|
|
}
|
|
|
|
const dLen = digitLength(num);
|
|
|
|
return dLen > 0 ? num * Math.pow(10, dLen) : num;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* 精确乘法
|
|
|
|
*/
|
|
|
|
function times(num1, num2) {
|
|
|
|
const others = [];
|
|
|
|
for (let _i = 2; _i < arguments.length; _i++) {
|
|
|
|
others[_i - 2] = arguments[_i];
|
|
|
|
}
|
|
|
|
if (others.length > 0) {
|
|
|
|
return times.apply(void 0, [times(num1, num2), others[0]].concat(others.slice(1)));
|
|
|
|
}
|
|
|
|
const num1Changed = float2Fixed(num1);
|
|
|
|
const num2Changed = float2Fixed(num2);
|
|
|
|
const baseNum = digitLength(num1) + digitLength(num2);
|
|
|
|
const leftValue = num1Changed * num2Changed;
|
|
|
|
return leftValue / Math.pow(10, baseNum);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* 精确除法
|
|
|
|
*/
|
|
|
|
function accDivide(num1, num2) {
|
|
|
|
const others = [];
|
|
|
|
for (let _i = 2; _i < arguments.length; _i++) {
|
|
|
|
others[_i - 2] = arguments[_i];
|
|
|
|
}
|
|
|
|
if (others.length > 0) {
|
|
|
|
return accDivide.apply(void 0, [accDivide(num1, num2), others[0]].concat(others.slice(1)));
|
|
|
|
}
|
|
|
|
const num1Changed = float2Fixed(num1);
|
|
|
|
const num2Changed = float2Fixed(num2);
|
|
|
|
return times((num1Changed / num2Changed), Math.pow(10, digitLength(num2) - digitLength(num1)));
|
|
|
|
}
|
|
|
|
}
|