## What This PR Does
1. Recover on, and provide a better message for, invalid `export` modifier on constructor parameters. Before, an `unexpected token` error would be produced and the parser would panic. Now, the parser recovers and produces a message saying `'export' modifier cannot appear on a parameter.`
```ts
class Foo {
constructor(export x: number) {}
}
```
2. Recover on, and provide a better message for, invalid modifiers on index signatures. Same recovery/message characteristics as above.
```ts
class Foo {
public [x: string]: string;
}
```
## What This PR Does
Provide better error messages when a reserved word is used as a `BindingIdentifier`
```ts
var const = 1;
export enum const {}
const if = 1;
```
Our convention is that AST type fields are ordered in order they appear in source. Move `type_parameters` fields in TS function declaration types to before `this_param` and formal parameters.
Use `BindingIdentifier` instead of `IdentifierName` so that AST visitors can access the bound symbol id for the namespace's name. This makes namespace consistent with other named declarations, such as `Class`, `Function`, and `TSInterfaceDeclaration`.
We should consider modifying `TSModuleDeclarationName::StringLiteral(...)` to also store a `symbol_id`, since one gets bound in semantic for it as well.
Quality-of-life improvement for invalid `const` modifiers on class elements. Instead of panicking, the parser will eat `const` and report it as an error.
```ts
class C {
static const H = 1;
}
```
Move post-transform checker into a `tasks` crate. It doesn't feel like it belongs in `oxc_semantic`. It also feels like too heavy a lump of code to put in `tasks/common`.
This PR makes 2 changes to improve the existing API that are not very useful.
- Remove `(Literal)Parser` and `FlagsParser` and their ASTs
- Add `with_flags(flags_text)` helper to `ParserOptions`
Here are the details.
> Remove `(Literal)Parser` and `FlagsParser` and their ASTs
Previously, the `oxc_regular_expression` crate exposed 3 parsers.
- `(Literal)Parser`: assumes `/pattern/flags` format
- `PatternParser`: assumes `pattern` part only
- `FlagsParser`: assumes `flags` part only
However, it turns out that in actual usecases, only the `PatternParser` is actually sufficient, as the pattern and flags are validated and sliced in advance on the `oxc_parser` side.
The current usecase for `(Literal)Parser` is mostly for internal testing.
There were also some misuses of `(Literal)Parser` that restore `format!("/{pattern}/{flags}")` back and use `(Literal)Parser`.
Therefore, only `PatternParser` is now published, and unnecessary ASTs have been removed.
(This also obsoletes #5592 .)
> Added `with_flags(flags_text)` helper to `ParserOptions`
Strictly speaking, there was a subtle difference between the "flag" strings that users were aware of and the "mode" recognised by the parser.
Therefore, it was a common mistake to forget to enable `unicode_mode` when using the `v` flag.
With this helper, crate users no longer need to distinguish between flags and modes.
An alternative version of #6177.
Convert `ModuleImports` into a common transform. Works much as before, but it inserts `import` / `require` statements by passing them to `TopLevelStatements` common transform, so they get inserted in one go with any other inserted top-level statements. This avoids shuffling up the `Vec<Statement>` multiple times, which can be slow with large files.
`VarDeclarations` also inserts any declarations via `TopLevelStatements` but runs after `ModuleImports`, so can control whether a `var` statement is inserted before or after `import` statements by inserting it via `VarDeclarations` (to appear after `import` statements) or directly into `TopLevelStatements` (to appear before `import` statements). Insertion order is not actually important, but allows us to match Babel's output and pass its tests.
`SymbolFlags::ArrowFunction` is an oddity, as whether a symbol is an arrow function is not statically knowable. In the following cases, `f` symbol did not have `ArrowFunction` flag set:
```js
const {f} = {f: () => {}};
```
```js
let f = 123;
f = () => {};
```
`SymbolFlags::ArrowFunction` is therefore not particularly useful, and possibly misleading. Having it complicates the transformer, and it's not used anywhere in Oxc.
This PR removes it.
### Difference
In `enter_expression`: Recursive transform JSX
In `exit_expression`: Deep first transform
After the change, `transform_jsx` still has a lot of room for improvement.
I expect small performance regression.
But managed to improve the following case from react.developmement.js
```
oxc main ❯ diff before.js after.js
670c670
< if (!(dispatcher !== null)) throw Error("Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for one of the following reasons:\n1. You might have mismatching versions of React and the renderer (such as React DOM)\n2. You might be breaking the Rules of Hooks\n3. You might have more than one copy of React in the same app\nSee https://reactjs.org/link/invalid-hook-call for tips about how to debug and fix this problem.");
---
> if (dispatcher === null) throw Error("Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for one of the following reasons:\n1. You might have mismatching versions of React and the renderer (such as React DOM)\n2. You might be breaking the Rules of Hooks\n3. You might have more than one copy of React in the same app\nSee https://reactjs.org/link/invalid-hook-call for tips about how to debug and fix this problem.");
```
See https://babel.dev/docs/options#misc-options for background on `unambiguous`
Once `SourceType::Unambiguous` is parsed, it will correctly set the returned `Program::source_type` to either `module` or `script`.
This also removes the confusing `SourceType::always_strict` field.
I hacked it with `SourceType::always_strict`, but what we actually want is add `'use strict'`.
This is technically a breaking change but I don't expect anyone using this outside of oxc.
The snapshot has a large diff due to every single line shifting by 1 row :-/
related: #4754
The implementation port from [esbuild](332727499e/internal/js_parser/js_parser.go (L12820-L12840)). And cover all babel's regexp plugins
---
## The following description was generated by `Graphite` 😋
### TL;DR
Added support for transforming various RegExp features to ensure compatibility with older JavaScript environments.
### What changed?
- Implemented a new `RegExp` transformer to handle unsupported RegExp literal features
- Added options to control different RegExp transformations (e.g., sticky flag, unicode flag, dot-all flag, etc.)
- Updated the transformer to convert unsupported RegExp literals into `new RegExp()` constructor calls
- Added test cases for different RegExp transformations
- Integrated the new RegExp transformer into the existing transformation pipeline
### How to test?
1. Run the existing test suite to ensure no regressions
2. Execute the new RegExp-specific tests in the `tasks/transform_conformance/tests/esbuild-tests/test/fixtures/regexp/` directory
3. Try transforming code with various RegExp features using different target environments to verify correct transformations
close: #5435
The behavior of `IdentifierReference` in `TSPropertySignature` is the same as in `TSTypeQuery`, both allow only reference value bindings and type-only import bindings.
I still use `ReferenceFlags::TSTypeQuery` here because I want to avoid producing many changes unrelated to the bug in this PR. I will refactor it in the follow-up PR soon
This should be causing more negative tests to fail than it actually is. This is
because our typescript coverage tests use the "declarations" option to change
the source type to `.d.ts`, which is incorrect. This setting enables `.d.ts`
emits, it does not mean that input files should be treated as `.d.ts`
themselves.
#5223 added a new variant `JSXElementName::IdentifierReference` for JSX identifiers which are treated as references (e.g. `<Foo>`) as opposed to `JSXElementName::Identifier` which is for lowercase (e.g. `<div>`).
But we were incorrectly categorizing identifiers beginning with `_` or `$` - these should also be treated as references.
(as discussed in https://github.com/oxc-project/oxc/pull/5339#issuecomment-2321037779)
Follow-on after #5223.
JSX identifiers which start with a capital letter are now `JSXElementName::IdentifierReference`s, so no need to check for capitalized `JSXElementName::Identifier`s.
