Fully support transforming ChainExpression in class properties. Our implementation has some differences in execution order compared to Babel, but we have passed all execution-related tests.
Similar to #7516. Fix class properties transform to replace references to class name in static prop initializers with temp var.
Input:
```js
class C {
static getSelf = () => C;
}
const C2 = C;
C = 123;
assert(C2.getSelf() === C);
```
Output:
```js
var _C;
class C {}
_C = C;
_defineProperty(C, "getSelf", () => _C);
const C2 = C;
C = 123;
assert(C2.getSelf() === C);
```
Previously, temp var wasn't used so code was `_defineProperty(C, "getSelf", () => C);`. `C` is altered later by `C = 123`, so `C2.getSelf()` returned `123`, instead of reference to the class.
Fix class properties transform to create a temp var for class when it's required.
Input:
```js
class C {
static getSelf = () => this;
}
const C2 = C;
C = 123;
assert(C2.getSelf() === C);
```
Output:
```js
var _C;
class C {}
_C = C;
_defineProperty(C, "getSelf", () => _C);
const C2 = C;
C = 123;
assert(C2.getSelf() === C);
```
Previously, temp var wasn't used so code was `_defineProperty(C, "getSelf", () => C);`. `C` is altered later by `C = 123`, so `C2.getSelf()` returned `123`, instead of reference to the class.
The logic around when a temp var is required and when it's not, and when/where it's referenced is ridiculously complicated. So add some debug assert mechanisms to double-check the logic.
Transform private property accesses in static prop initializers. e.g.:
Input:
```js
class C {
static #x = 123;
static y = this.#x;
}
```
Transformed:
```js
class C {}
var _x = { _: 123 };
babelHelpers.defineProperty(C, "y", babelHelpers.assertClassBrand(C, C, _x)._);
```
`this.#x` has been transformed to `babelHelpers.assertClassBrand(C, C, _x)._`.
Add class properties transform.
Implementation is incomplete. Notable missing parts:
* Scopes are not updated where property initializers move from class body into class constructor / `_super` function.
* Does not handle binding shadowing problems when property initializers move from class body into class constructor.
* `this` and references to class name in static property initializers need to be transformed to point to a temp var.
* Not all usages of private properties are supported (see below).
* Code which is moved to outside of class body is not transformed by other transforms for class declarations (works OK for class expressions). This includes static property initializers, static blocks, and computed property/method keys.
* Only basic checks for whether computed property/method keys may have side effects.
* Numerous other small issues noted in TODO comments through the code.
### Private properties
Currently does not handle the following usages of private properties:
```js
class Class {
#prop;
static #static;
method() {
object?.#prop;
object?.#prop();
[object.#prop] = [1];
({x: object.#prop} = {x: 1});
object.#prop`xyz`;
object?.#static;
object?.#static();
[object.#static] = [1];
({x: object.#static} = {x: 1});
object.#static`xyz`;
}
}
```
Part of https://github.com/oxc-project/oxc/pull/7074
In async-to-generator and async-generator-functions plugins, we may need to transform the async arrow function to a regular generator function, now we can reuse the ability of the ArrowFunction plugin by enabling `ArrowFunctionConverter`.
I will fix semantic errors in the follow-up PR
Passed 15/19 tests. The remaining 4 failed tests related to `this` expression, the problem same as I mentioned in #6658. I will fix them in follow-up PRs.
