v0.28.0

• Add support for with { type: 'text' } imports (#4435)

  The import text proposal has reached stage 3 in the TC39 process, which means that it's recommended for implementation. It has also already been implemented by Deno and Bun. So with this release, esbuild also adds support for it. This behaves exactly the same as esbuild's existing text loader. Here's an example:

  import string from './example.txt' with { type: 'text' }
  console.log(string)

• Add integrity checks to fallback download path (#4343)

  Installing esbuild via npm is somewhat complicated with several different edge cases (see esbuild's documentation for details). If the regular installation of esbuild's platform-specific package fails, esbuild's install script attempts to download the platform-specific package itself (first with the npm command, and then with a HTTP request to registry.npmjs.org as a last resort).

  This last resort path previously didn't have any integrity checks. With this release, esbuild will now verify that the hash of the downloaded binary matches the expected hash for the current release. This means the hashes for all of esbuild's platform-specific binary packages will now be embedded in the top-level esbuild package. Hopefully this should work without any problems. But just in case, this change is being done as a breaking change release.

• Update the Go compiler from 1.25.7 to 1.26.1

  This upgrade should not affect anything. However, there have been some significant internal changes to the Go compiler, so esbuild could potentially behave differently in certain edge cases:

  • It now uses the new garbage collector that comes with Go 1.26.
  • The Go compiler is now more aggressive with allocating memory on the stack.
  • The executable format that the Go linker uses has undergone several changes.
  • The WebAssembly build now unconditionally makes use of the sign extension and non-trapping floating-point to integer conversion instructions.

  You can read the Go 1.26 release notes for more information.

v0.27.7

• Fix lowering of define semantics for TypeScript parameter properties (#4421)

  The previous release incorrectly generated class fields for TypeScript parameter properties even when the configured target environment does not support class fields. With this release, the generated class fields will now be correctly lowered in this case:

  // Original code
  class Foo {
    constructor(public x = 1) {}
    y = 2
  }
  
  // Old output (with --loader=ts --target=es2021)
  class Foo {
    constructor(x = 1) {
      this.x = x;
      __publicField(this, "y", 2);
    }
    x;
  }
  
  // New output (with --loader=ts --target=es2021)
  class Foo {
    constructor(x = 1) {
      __publicField(this, "x", x);
      __publicField(this, "y", 2);
    }
  }

v0.27.5

• Fix for an async generator edge case (#4401, #4417)

  Support for transforming async generators into the equivalent state machine was added in version 0.19.0. However, the generated state machine didn't work correctly when polling async generators concurrently, such as in the following code:

  async function* inner() { yield 1; yield 2 }
  async function* outer() { yield* inner() }
  let gen = outer()
  for await (let x of [gen.next(), gen.next()]) console.log(x)

  Previously esbuild's output of the above code behaved incorrectly when async generators were transformed (such as with --supported:async-generator=false). The transformation should be fixed starting with this release.

  This fix was contributed by @2767mr.

• Fix a regression when metafile is enabled (#4420, #4418)

  This release fixes a regression introduced by the previous release. When metafile: true was enabled in esbuild's JavaScript API, builds with build errors were incorrectly throwing an error about an empty JSON string instead of an object containing the build errors.

• Use define semantics for TypeScript parameter properties (#4421)

  Parameter properties are a TypeScript-specific code generation feature that converts constructor parameters into class fields when they are prefixed by certain keywords. When "useDefineForClassFields": true is present in tsconfig.json, the TypeScript compiler automatically generates class field declarations for parameter properties. Previously esbuild didn't do this, but esbuild will now do this starting with this release:

  // Original code
  class Foo {
    constructor(public x: number) {}
  }
  
  // Old output (with --loader=ts)
  class Foo {
    constructor(x) {
      this.x = x;
    }
  }
  
  // New output (with --loader=ts)
  class Foo {
    constructor(x) {
      this.x = x;
    }
    x;
  }

• Allow es2025 as a target in tsconfig.json (#4432)

  TypeScript recently added es2025 as a compilation target, so esbuild now supports this in the target field of tsconfig.json files, such as in the following configuration file:

  {
    "compilerOptions": {
      "target": "ES2025"
    }
  }

  As a reminder, the only thing that esbuild uses this field for is determining whether or not to use legacy TypeScript behavior for class fields. You can read more in the documentation.

v0.27.4

• Fix a regression with CSS media queries (#4395, #4405, #4406)

  Version 0.25.11 of esbuild introduced support for parsing media queries. This unintentionally introduced a regression with printing media queries that use the <media-type> and <media-condition-without-or> grammar. Specifically, esbuild was failing to wrap an or clause with parentheses when inside <media-condition-without-or>. This release fixes the regression.

  Here is an example:

  /* Original code */
  @media only screen and ((min-width: 10px) or (min-height: 10px)) {
    a { color: red }
  }
  
  /* Old output (incorrect) */
  @media only screen and (min-width: 10px) or (min-height: 10px) {
    a {
      color: red;
    }
  }
  
  /* New output (correct) */
  @media only screen and ((min-width: 10px) or (min-height: 10px)) {
    a {
      color: red;
    }
  }

• Fix an edge case with the inject feature (#4407)

  This release fixes an edge case where esbuild's inject feature could not be used with arbitrary module namespace names exported using an export {} from statement with bundling disabled and a target environment where arbitrary module namespace names is unsupported.

  With the fix, the following inject file:

  import jquery from 'jquery';
  export { jquery as 'window.jQuery' };

  Can now always be rewritten as this without esbuild sometimes incorrectly generating an error:

  export { default as 'window.jQuery' } from 'jquery';

• Attempt to improve API handling of huge metafiles (#4329, #4415)

  This release contains a few changes that attempt to improve the behavior of esbuild's JavaScript API with huge metafiles (esbuild's name for the build metadata, formatted as a JSON object). The JavaScript API is designed to return the metafile JSON as a JavaScript object in memory, which makes it easy to access from within a JavaScript-based plugin. Multiple people have encountered issues where this API breaks down with a pathologically-large metafile.

  The primary issue is that V8 has an implementation-specific maximum string length, so using the JSON.parse API with large enough strings is impossible. This release will now attempt to use a fallback JavaScript-based JSON parser that operates directly on the UTF8-encoded JSON bytes instead of using JSON.parse when the JSON metafile is too big to fit in a JavaScript string. The new fallback path has not yet been heavily-tested. The metafile will also now be generated with whitespace removed if the bundle is significantly large, which will reduce the size of the metafile JSON slightly.

  However, hitting this case is potentially a sign that something else is wrong. Ideally you wouldn't be building something so enormous that the build metadata can't even fit inside a JavaScript string. You may want to consider optimizing your project, or breaking up your project into multiple parts that are built independently. Another option could potentially be to use esbuild's command-line API instead of its JavaScript API, which is more efficient (although of course then you can't use JavaScript plugins, so it may not be an option).

v0.27.3

• Preserve URL fragments in data URLs (#4370)

  Consider the following HTML, CSS, and SVG:

  • index.html:

    <!DOCTYPE html>
    <html>
      <head><link rel="stylesheet" href="icons.css"></head>
      <body><div class="triangle"></div></body>
    </html>

  • icons.css:

    .triangle {
      width: 10px;
      height: 10px;
      background: currentColor;
      clip-path: url(./triangle.svg#x);
    }

  • triangle.svg:

    <svg xmlns="http://www.w3.org/2000/svg">
      <defs>
        <clipPath id="x">
          <path d="M0 0H10V10Z"/>
        </clipPath>
      </defs>
    </svg>

  The CSS uses a URL fragment (the #x) to reference the clipPath element in the SVG file. Previously esbuild's CSS bundler didn't preserve the URL fragment when bundling the SVG using the dataurl loader, which broke the bundled CSS. With this release, esbuild will now preserve the URL fragment in the bundled CSS:

  /* icons.css */
  .triangle {
    width: 10px;
    height: 10px;
    background: currentColor;
    clip-path: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg"><defs><clipPath id="x"><path d="M0 0H10V10Z"/></clipPath></defs></svg>#x');
  }

• Parse and print CSS @scope rules (#4322)

  This release includes dedicated support for parsing @scope rules in CSS. These rules include optional "start" and "end" selector lists. One important consequence of this is that the local/global status of names in selector lists is now respected, which improves the correctness of esbuild's support for CSS modules. Minification of selectors inside @scope rules has also improved slightly.

  Here's an example:

  /* Original code */
  @scope (:global(.foo)) to (:local(.bar)) {
    .bar {
      color: red;
    }
  }
  
  /* Old output (with --loader=local-css --minify) */
  @scope (:global(.foo)) to (:local(.bar)){.o{color:red}}
  
  /* New output (with --loader=local-css --minify) */
  @scope(.foo)to (.o){.o{color:red}}

• Fix a minification bug with lowering of for await (#4378, #4385)

  This release fixes a bug where the minifier would incorrectly strip the variable in the automatically-generated catch clause of lowered for await loops. The code that generated the loop previously failed to mark the internal variable references as used.

• Update the Go compiler from v1.25.5 to v1.25.7 (#4383, #4388)

  This PR was contributed by @MikeWillCook.

v0.27.2

• Allow import path specifiers starting with #/ (#4361)

  Previously the specification for package.json disallowed import path specifiers starting with #/, but this restriction has recently been relaxed and support for it is being added across the JavaScript ecosystem. One use case is using it for a wildcard pattern such as mapping #/* to ./src/* (previously you had to use another character such as #_* instead, which was more confusing). There is some more context in nodejs/node#49182.

  This change was contributed by @hybrist.

• Automatically add the -webkit-mask prefix (#4357, #4358)

  This release automatically adds the -webkit- vendor prefix for the mask CSS shorthand property:

  /* Original code */
  main {
    mask: url(x.png) center/5rem no-repeat
  }
  
  /* Old output (with --target=chrome110) */
  main {
    mask: url(x.png) center/5rem no-repeat;
  }
  
  /* New output (with --target=chrome110) */
  main {
    -webkit-mask: url(x.png) center/5rem no-repeat;
    mask: url(x.png) center/5rem no-repeat;
  }

  This change was contributed by @BPJEnnova.

• Additional minification of switch statements (#4176, #4359)

  This release contains additional minification patterns for reducing switch statements. Here is an example:

  // Original code
  switch (x) {
    case 0:
      foo()
      break
    case 1:
    default:
      bar()
  }
  
  // Old output (with --minify)
  switch(x){case 0:foo();break;case 1:default:bar()}
  
  // New output (with --minify)
  x===0?foo():bar();

• Forbid using declarations inside switch clauses (#4323)

  This is a rare change to remove something that was previously possible. The Explicit Resource Management proposal introduced using declarations. These were previously allowed inside case and default clauses in switch statements. This had well-defined semantics and was already widely implemented (by V8, SpiderMonkey, TypeScript, esbuild, and others). However, it was considered to be too confusing because of how scope works in switch statements, so it has been removed from the specification. This edge case will now be a syntax error. See tc39/proposal-explicit-resource-management#215 and rbuckton/ecma262#14 for details.

  Here is an example of code that is no longer allowed:

  switch (mode) {
    case 'read':
      using readLock = db.read()
      return readAll(readLock)
  
    case 'write':
      using writeLock = db.write()
      return writeAll(writeLock)
  }

  That code will now have to be modified to look like this instead (note the additional { and } block statements around each case body):

  switch (mode) {
    case 'read': {
      using readLock = db.read()
      return readAll(readLock)
    }
    case 'write': {
      using writeLock = db.write()
      return writeAll(writeLock)
    }
  }

  This is not being released in one of esbuild's breaking change releases since this feature hasn't been finalized yet, and esbuild always tracks the current state of the specification (so esbuild's previous behavior was arguably incorrect).

v0.27.1

• Fix bundler bug with var nested inside if (#4348)

  This release fixes a bug with the bundler that happens when importing an ES module using require (which causes it to be wrapped) and there's a top-level var inside an if statement without being wrapped in a { ... } block (and a few other conditions). The bundling transform needed to hoist these var declarations outside of the lazy ES module wrapper for correctness. See the issue for details.

• Fix minifier bug with for inside try inside label (#4351)

  This fixes an old regression from version v0.21.4. Some code was introduced to move the label inside the try statement to address a problem with transforming labeled for await loops to avoid the await (the transformation involves converting the for await loop into a for loop and wrapping it in a try statement). However, it introduces problems for cross-compiled JVM code that uses all three of these features heavily. This release restricts this transform to only apply to for loops that esbuild itself generates internally as part of the for await transform. Here is an example of some affected code:

  // Original code
  d: {
    e: {
      try {
        while (1) { break d }
      } catch { break e; }
    }
  }
  
  // Old output (with --minify)
  a:try{e:for(;;)break a}catch{break e}
  
  // New output (with --minify)
  a:e:try{for(;;)break a}catch{break e}

• Inline IIFEs containing a single expression (#4354)

  Previously inlining of IIFEs (immediately-invoked function expressions) only worked if the body contained a single return statement. Now it should also work if the body contains a single expression statement instead:

  // Original code
  const foo = () => {
    const cb = () => {
      console.log(x())
    }
    return cb()
  }
  
  // Old output (with --minify)
  const foo=()=>(()=>{console.log(x())})();
  
  // New output (with --minify)
  const foo=()=>{console.log(x())};

• The minifier now strips empty finally clauses (#4353)

  This improvement means that finally clauses containing dead code can potentially cause the associated try statement to be removed from the output entirely in minified builds:

  // Original code
  function foo(callback) {
    if (DEBUG) stack.push(callback.name);
    try {
      callback();
    } finally {
      if (DEBUG) stack.pop();
    }
  }
  
  // Old output (with --minify --define:DEBUG=false)
  function foo(a){try{a()}finally{}}
  
  // New output (with --minify --define:DEBUG=false)
  function foo(a){a()}

• Allow tree-shaking of the Symbol constructor

  With this release, calling Symbol is now considered to be side-effect free when the argument is known to be a primitive value. This means esbuild can now tree-shake module-level symbol variables:

  // Original code
  const a = Symbol('foo')
  const b = Symbol(bar)
  
  // Old output (with --tree-shaking=true)
  const a = Symbol("foo");
  const b = Symbol(bar);
  
  // New output (with --tree-shaking=true)
  const b = Symbol(bar);

v0.27.0

This release deliberately contains backwards-incompatible changes. To avoid automatically picking up releases like this, you should either be pinning the exact version of esbuild in your package.json file (recommended) or be using a version range syntax that only accepts patch upgrades such as ^0.26.0 or ~0.26.0. See npm's documentation about semver for more information.

• Use Uint8Array.fromBase64 if available (#4286)

  With this release, esbuild's binary loader will now use the new Uint8Array.fromBase64 function unless it's unavailable in the configured target environment. If it's unavailable, esbuild's previous code for this will be used as a fallback. Note that this means you may now need to specify target when using this feature with Node (for example --target=node22) unless you're using Node v25+.

• Update the Go compiler from v1.23.12 to v1.25.4 (#4208, #4311)

  This raises the operating system requirements for running esbuild:

  • Linux: now requires a kernel version of 3.2 or later
  • macOS: now requires macOS 12 (Monterey) or later

v0.26.0

• Enable trusted publishing (#4281)

  GitHub and npm are recommending that maintainers for packages such as esbuild switch to trusted publishing. With this release, a VM on GitHub will now build and publish all of esbuild's packages to npm instead of me. In theory.

  Unfortunately there isn't really a way to test that this works other than to do it live. So this release is that live test. Hopefully this release is uneventful and is exactly the same as the previous one (well, except for the green provenance attestation checkmark on npm that happens with trusted publishing).

v0.25.12

• Fix a minification regression with CSS media queries (#4315)

  The previous release introduced support for parsing media queries which unintentionally introduced a regression with the removal of duplicate media rules during minification. Specifically the grammar for @media <media-type> and <media-condition-without-or> { ... } was missing an equality check for the <media-condition-without-or> part, so rules with different suffix clauses in this position would incorrectly compare equal and be deduplicated. This release fixes the regression.

• Update the list of known JavaScript globals (#4310)

  This release updates esbuild's internal list of known JavaScript globals. These are globals that are known to not have side-effects when the property is accessed. For example, accessing the global Array property is considered to be side-effect free but accessing the global scrollY property can trigger a layout, which is a side-effect. This is used by esbuild's tree-shaking to safely remove unused code that is known to be side-effect free. This update adds the following global properties:

  From ES2017:

  • Atomics
  • SharedArrayBuffer

  From ES2020:

  • BigInt64Array
  • BigUint64Array

  From ES2021:

  • FinalizationRegistry
  • WeakRef

  From ES2025:

  • Float16Array
  • Iterator

  Note that this does not indicate that constructing any of these objects is side-effect free, just that accessing the identifier is side-effect free. For example, this now allows esbuild to tree-shake classes that extend from Iterator:

  // This can now be tree-shaken by esbuild:
  class ExampleIterator extends Iterator {}

• Add support for the new @view-transition CSS rule (#4313)

  With this release, esbuild now has improved support for pretty-printing and minifying the new @view-transition rule (which esbuild was previously unaware of):

  /* Original code */
  @view-transition {
    navigation: auto;
    types: check;
  }
  
  /* Old output */
  @view-transition { navigation: auto; types: check; }
  
  /* New output */
  @view-transition {
    navigation: auto;
    types: check;
  }

  The new view transition feature provides a mechanism for creating animated transitions between documents in a multi-page app. You can read more about view transition rules here.

  This change was contributed by @yisibl.

• Trim CSS rules that will never match

  The CSS minifier will now remove rules whose selectors contain :is() and :where() as those selectors will never match. These selectors can currently be automatically generated by esbuild when you give esbuild nonsensical input such as the following:

  /* Original code */
  div:before {
    color: green;
    &.foo {
      color: red;
    }
  }
  
  /* Old output (with --supported:nesting=false --minify) */
  div:before{color:green}:is().foo{color:red}
  
  /* New output (with --supported:nesting=false --minify) */
  div:before{color:green}

  This input is nonsensical because CSS nesting is (unfortunately) not supported inside of pseudo-elements such as :before. Currently esbuild generates a rule containing :is() in this case when you tell esbuild to transform nested CSS into non-nested CSS. I think it's reasonable to do that as it sort of helps explain what's going on (or at least indicates that something is wrong in the output). It shouldn't be present in minified code, however, so this release now strips it out.