This Pull Request closes#1975. It's still a work in progress, but tries to go in that direction.
It changes the following:
- Adds a new `TryFromJs` trait, that can be derived using a new `boa_derive` crate.
- Adds a new `try_js_into()` function that, similarly to the standard library `TryInto` trait
Things to think about:
- Should the `boa_derive` crate be re-exported in `boa_engine` using a `derive` feature, similar to how it's done in `serde`?
- The current implementation only converts perfectly valid values. So, if we try to convert a big integer into an `i8`, or any floating point number to an `f32`. So, you cannot derive `TryFromJs` for structures that contain an `f32` for example (you can still manually implement the trait, though, and decide in favour of a loss of precision). Should we also provide some traits for transparent loss of precision?
- Currently, you cannot convert between types, so if the JS struct has an integer, you cannot cast it to a boolean, for example. Should we provide a `TryConvertJs` trait, for example to force conversions?
- Currently we only have basic types and object conversions. Should add `Array` to `Vec` conversion, for example, right? Should we also add `TypedArray` conversions? What about `Map` and `Set`? Does this step over the fine grained APIs that we were creating?
Note that this still requires a bunch of documentation, tests, and validation from the dev team and from the users that requested this feature. I'm particularly interested in @lastmjs's thoughts on this API.
I already added an usage example in `boa_examples/src/bin/derive.rs`.
Co-authored-by: jedel1043 <jedel0124@gmail.com>
José Julián Espina
Iban Eguia Moraza