The previous release introduced a regression with the --keep-names setting and object literals with get/set accessor methods, in which case the generated code contained syntax errors. This release fixes the regression:
// Original code
x = { get y() {} }
// Output from version 0.21.0 (with --keep-names)
x = { get y: /* @PURE */ __name(function() {
}, "y") };
// Output from this version (with --keep-names)
x = { get y() {
} };
v0.21.0
This release doesn't contain any deliberately-breaking changes. However, it contains a very complex new feature and while all of esbuild's tests pass, I would not be surprised if an important edge case turns out to be broken. So I'm releasing this as a breaking change release to avoid causing any trouble. As usual, make sure to test your code when you upgrade.
Implement the JavaScript decorators proposal (#104)
With this release, esbuild now contains an implementation of the upcoming JavaScript decorators proposal. This is the same feature that shipped in TypeScript 5.0 and has been highly-requested on esbuild's issue tracker. You can read more about them in that blog post and in this other (now slightly outdated) extensive blog post here: https://2ality.com/2022/10/javascript-decorators.html. Here's a quick example:
const log = (fn, context) => function() {
console.log(`before ${context.name}`)
const it = fn.apply(this, arguments)
console.log(`after ${context.name}`)
return it
}
// Logs "before foo", "in foo", "after foo"
Foo.foo()
Note that this feature is different than the existing "TypeScript experimental decorators" feature that esbuild already implements. It uses similar syntax but behaves very differently, and the two are not compatible (although it's sometimes possible to write decorators that work with both). TypeScript experimental decorators will still be supported by esbuild going forward as they have been around for a long time, are very widely used, and let you do certain things that are not possible with JavaScript decorators (such as decorating function parameters). By default esbuild will parse and transform JavaScript decorators, but you can tell esbuild to parse and transform TypeScript experimental decorators instead by setting "experimentalDecorators": true in your tsconfig.json file.
Probably at least half of the work for this feature went into creating a test suite that exercises many of the proposal's edge cases: https://github.com/evanw/decorator-tests. It has given me a reasonable level of confidence that esbuild's initial implementation is acceptable. However, I don't have access to a significant sample of real code that uses JavaScript decorators. If you're currently using JavaScript decorators in a real code base, please try out esbuild's implementation and let me know if anything seems off.
⚠️ WARNING ⚠️
This proposal has been in the works for a very long time (work began around 10 years ago in 2014) and it is finally getting close to becoming part of the JavaScript language. However, it's still a work in progress and isn't a part of JavaScript yet, so keep in mind that any code that uses JavaScript decorators may need to be updated as the feature continues to evolve. The decorators proposal is pretty close to its final form but it can and likely will undergo some small behavioral adjustments before it ends up becoming a part of the standard. If/when that happens, I will update esbuild's implementation to match the specification. I will not be supporting old versions of the specification.
The previous release introduced a regression with the --keep-names setting and object literals with get/set accessor methods, in which case the generated code contained syntax errors. This release fixes the regression:
// Original code
x = { get y() {} }
// Output from version 0.21.0 (with --keep-names)
x = { get y: /* @PURE */ __name(function() {
}, "y") };
// Output from this version (with --keep-names)
x = { get y() {
} };
0.21.0
This release doesn't contain any deliberately-breaking changes. However, it contains a very complex new feature and while all of esbuild's tests pass, I would not be surprised if an important edge case turns out to be broken. So I'm releasing this as a breaking change release to avoid causing any trouble. As usual, make sure to test your code when you upgrade.
Implement the JavaScript decorators proposal (#104)
With this release, esbuild now contains an implementation of the upcoming JavaScript decorators proposal. This is the same feature that shipped in TypeScript 5.0 and has been highly-requested on esbuild's issue tracker. You can read more about them in that blog post and in this other (now slightly outdated) extensive blog post here: https://2ality.com/2022/10/javascript-decorators.html. Here's a quick example:
const log = (fn, context) => function() {
console.log(`before ${context.name}`)
const it = fn.apply(this, arguments)
console.log(`after ${context.name}`)
return it
}
// Logs "before foo", "in foo", "after foo"
Foo.foo()
Note that this feature is different than the existing "TypeScript experimental decorators" feature that esbuild already implements. It uses similar syntax but behaves very differently, and the two are not compatible (although it's sometimes possible to write decorators that work with both). TypeScript experimental decorators will still be supported by esbuild going forward as they have been around for a long time, are very widely used, and let you do certain things that are not possible with JavaScript decorators (such as decorating function parameters). By default esbuild will parse and transform JavaScript decorators, but you can tell esbuild to parse and transform TypeScript experimental decorators instead by setting "experimentalDecorators": true in your tsconfig.json file.
Probably at least half of the work for this feature went into creating a test suite that exercises many of the proposal's edge cases: https://github.com/evanw/decorator-tests. It has given me a reasonable level of confidence that esbuild's initial implementation is acceptable. However, I don't have access to a significant sample of real code that uses JavaScript decorators. If you're currently using JavaScript decorators in a real code base, please try out esbuild's implementation and let me know if anything seems off.
Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.
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⚠️ Dependabot is rebasing this PR ⚠️
Rebasing might not happen immediately, so don't worry if this takes some time.
Note: if you make any changes to this PR yourself, they will take precedence over the rebase.
Bumps esbuild from 0.20.0 to 0.21.1.
Release notes
Sourced from esbuild's releases.
... (truncated)
Changelog
Sourced from esbuild's changelog.
... (truncated)
Commits
e876394
publish 0.21.1 to npm4abc387
adjust decorator source map locationse7a9256
fix #3756: regression with--keep-names
33cbbea
runmake update-compat-table
c6da2c3
publish 0.21.0 to npm4bc834c
initial implementation of the decorators proposal (#3754)07cdbe0
some small adjustments to runtime library code71b3d9f
split offlowerPrivateMethod
fromlowerMethod
0861625
printer: preserve single-line status of block bodyf426153
runtime: make some helper functions more compactDependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting
@dependabot rebase
.Dependabot commands and options
You can trigger Dependabot actions by commenting on this PR: - `@dependabot rebase` will rebase this PR - `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it - `@dependabot merge` will merge this PR after your CI passes on it - `@dependabot squash and merge` will squash and merge this PR after your CI passes on it - `@dependabot cancel merge` will cancel a previously requested merge and block automerging - `@dependabot reopen` will reopen this PR if it is closed - `@dependabot close` will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually - `@dependabot show