chore(deps): update dependency esbuild to v0.19.2 - autoclosed

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
esbuild	0.18.5 -> 0.19.2

---

Release Notes

evanw/esbuild (esbuild)

v0.19.2

Compare Source

• Update how CSS nesting is parsed again

  CSS nesting syntax has been changed again, and esbuild has been updated to match. Type selectors may now be used with CSS nesting:

  .foo {
    div {
      color: red;
    }
  }

  Previously this was disallowed in the CSS specification because it's ambiguous whether an identifier is a declaration or a nested rule starting with a type selector without requiring unbounded lookahead in the parser. It has now been allowed because the CSS working group has decided that requiring unbounded lookahead is acceptable after all.

  Note that this change means esbuild no longer considers any existing browser to support CSS nesting since none of the existing browsers support this new syntax. CSS nesting will now always be transformed when targeting a browser. This situation will change in the future as browsers add support for this new syntax.

• Fix a scope-related bug with --drop-labels= (#​3311)

  The recently-released --drop-labels= feature previously had a bug where esbuild's internal scope stack wasn't being restored properly when a statement with a label was dropped. This could manifest as a tree-shaking issue, although it's possible that this could have also been causing other subtle problems too. The bug has been fixed in this release.

• Make renamed CSS names unique across entry points (#​3295)

  Previously esbuild's generated names for local names in CSS were only unique within a given entry point (or across all entry points when code splitting was enabled). That meant that building multiple entry points with esbuild could result in local names being renamed to the same identifier even when those entry points were built simultaneously within a single esbuild API call. This problem was especially likely to happen with minification enabled. With this release, esbuild will now avoid renaming local names from two separate entry points to the same name if those entry points were built with a single esbuild API call, even when code splitting is disabled.

• Fix CSS ordering bug with @layer before @import

  CSS lets you put @layer rules before @import rules to define the order of layers in a stylesheet. Previously esbuild's CSS bundler incorrectly ordered these after the imported files because before the introduction of cascade layers to CSS, imported files could be bundled by removing the @import rules and then joining files together in the right order. But with @layer, CSS files may now need to be split apart into multiple pieces in the bundle. For example:

  /* Original code */
  @​layer start;
  @​import "data:text/css,@​layer inner.start;";
  @​import "data:text/css,@​layer inner.end;";
  @​layer end;
  
  /* Old output (with --bundle) */
  @​layer inner.start;
  @​layer inner.end;
  @​layer start;
  @​layer end;
  
  /* New output (with --bundle) */
  @​layer start;
  @​layer inner.start;
  @​layer inner.end;
  @​layer end;
  

• Unwrap nested duplicate @media rules (#​3226)

  With this release, esbuild's CSS minifier will now automatically unwrap duplicate nested @media rules:

  /* Original code */
  @​media (min-width: 1024px) {
    .foo { color: red }
    @​media (min-width: 1024px) {
      .bar { color: blue }
    }
  }
  
  /* Old output (with --minify) */
  @​media (min-width: 1024px){.foo{color:red}@​media (min-width: 1024px){.bar{color:#​00f}}}
  
  /* New output (with --minify) */
  @​media (min-width: 1024px){.foo{color:red}.bar{color:#​00f}}

  These rules are unlikely to be authored manually but may result from using frameworks such as Tailwind to generate CSS.

v0.19.1

Compare Source

• Fix a regression with baseURL in tsconfig.json (#​3307)

  The previous release moved tsconfig.json path resolution before --packages=external checks to allow the paths field in tsconfig.json to avoid a package being marked as external. However, that reordering accidentally broke the behavior of the baseURL field from tsconfig.json. This release moves these path resolution rules around again in an attempt to allow both of these cases to work.

• Parse TypeScript type arguments for JavaScript decorators (#​3308)

  When parsing JavaScript decorators in TypeScript (i.e. with experimentalDecorators disabled), esbuild previously didn't parse type arguments. Type arguments will now be parsed starting with this release. For example:

  @&#8203;foo<number>
  @&#8203;bar<number, string>()
  class Foo {}

• Fix glob patterns matching extra stuff at the end (#​3306)

  Previously glob patterns such as ./*.js would incorrectly behave like ./*.js* during path matching (also matching .js.map files, for example). This was never intentional behavior, and has now been fixed.

• Change the permissions of esbuild's generated output files (#​3285)

  This release changes the permissions of the output files that esbuild generates to align with the default behavior of node's fs.writeFileSync function. Since most tools written in JavaScript use fs.writeFileSync, this should make esbuild more consistent with how other JavaScript build tools behave.

  The full Unix-y details: Unix permissions use three-digit octal notation where the three digits mean "user, group, other" in that order. Within a digit, 4 means "read" and 2 means "write" and 1 means "execute". So 6 == 4 + 2 == read + write. Previously esbuild uses 0644 permissions (the leading 0 means octal notation) but the permissions for fs.writeFileSync defaults to 0666, so esbuild will now use 0666 permissions. This does not necessarily mean that the files esbuild generates will end up having 0666 permissions, however, as there is another Unix feature called "umask" where the operating system masks out some of these bits. If your umask is set to 0022 then the generated files will have 0644 permissions, and if your umask is set to 0002 then the generated files will have 0664 permissions.

• Fix a subtle CSS ordering issue with @import and @layer

  With this release, esbuild may now introduce additional @layer rules when bundling CSS to better preserve the layer ordering of the input code. Here's an example of an edge case where this matters:

  /* entry.css */
  @​import "a.css";
  @​import "b.css";
  @​import "a.css";

  /* a.css */
  @​layer a {
    body {
      background: red;
    }
  }

  /* b.css */
  @​layer b {
    body {
      background: green;
    }
  }

  This CSS should set the body background to green, which is what happens in the browser. Previously esbuild generated the following output which incorrectly sets the body background to red:

  /* b.css */
  @​layer b {
    body {
      background: green;
    }
  }
  
  /* a.css */
  @​layer a {
    body {
      background: red;
    }
  }

  This difference in behavior is because the browser evaluates a.css + b.css + a.css (in CSS, each @import is replaced with a copy of the imported file) while esbuild was only writing out b.css + a.css. The first copy of a.css wasn't being written out by esbuild for two reasons: 1) bundlers care about code size and try to avoid emitting duplicate CSS and 2) when there are multiple copies of a CSS file, normally only the last copy matters since the last declaration with equal specificity wins in CSS.

  However, @layer was recently added to CSS and for @layer the first copy matters because layers are ordered using their first location in source code order. This introduction of @layer means esbuild needs to change its bundling algorithm. An easy solution would be for esbuild to write out a.css twice, but that would be inefficient. So what I'm going to try to have esbuild do with this release is to write out an abbreviated form of the first copy of a CSS file that only includes the @layer information, and then still only write out the full CSS file once for the last copy. So esbuild's output for this edge case now looks like this:

  /* a.css */
  @​layer a;
  
  /* b.css */
  @​layer b {
    body {
      background: green;
    }
  }
  
  /* a.css */
  @​layer a {
    body {
      background: red;
    }
  }

  The behavior of the bundled CSS now matches the behavior of the unbundled CSS. You may be wondering why esbuild doesn't just write out a.css first followed by b.css. That would work in this case but it doesn't work in general because for any rules outside of a @layer rule, the last copy should still win instead of the first copy.

• Fix a bug with esbuild's TypeScript type definitions (#​3299)

  This release fixes a copy/paste error with the TypeScript type definitions for esbuild's JS API:

   export interface TsconfigRaw {
     compilerOptions?: {
  -    baseUrl?: boolean
  +    baseUrl?: string
       ...
     }
   }

  This fix was contributed by @​privatenumber.

v0.19.0

Compare Source

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 ^0.18.0 or ~0.18.0. See npm's documentation about semver for more information.

• Handle import paths containing wildcards (#​56, #​700, #​875, #​976, #​2221, #​2515)

  This release introduces wildcards in import paths in two places:

  • Entry points

    You can now pass a string containing glob-style wildcards such as ./src/*.ts as an entry point and esbuild will search the file system for files that match the pattern. This can be used to easily pass esbuild all files with a certain extension on the command line in a cross-platform way. Previously you had to rely on the shell to perform glob expansion, but that is obviously shell-dependent and didn't work at all on Windows. Note that to use this feature on the command line you will have to quote the pattern so it's passed verbatim to esbuild without any expansion by the shell. Here's an example:

    esbuild --minify "./src/*.ts" --outdir=out

    Specifically the * character will match any character except for the / character, and the /**/ character sequence will match a path separator followed by zero or more path elements. Other wildcard operators found in glob patterns such as ? and [...] are not supported.

  • Run-time import paths

    Import paths that are evaluated at run-time can now be bundled in certain limited situations. The import path expression must be a form of string concatenation and must start with either ./ or ../. Each non-string expression in the string concatenation chain becomes a wildcard. The * wildcard is chosen unless the previous character is a /, in which case the /**/* character sequence is used. Some examples:

    // These two forms are equivalent
    const json1 = await import('./data/' + kind + '.json')
    const json2 = await import(`./data/${kind}.json`)

    This feature works with require(...) and import(...) because these can all accept run-time expressions. It does not work with import and export statements because these cannot accept run-time expressions. If you want to prevent esbuild from trying to bundle these imports, you should move the string concatenation expression outside of the require(...) or import(...). For example:

    // This will be bundled
    const json1 = await import('./data/' + kind + '.json')
    
    // This will not be bundled
    const path = './data/' + kind + '.json'
    const json2 = await import(path)

    Note that using this feature means esbuild will potentially do a lot of file system I/O to find all possible files that might match the pattern. This is by design, and is not a bug. If this is a concern, I recommend either avoiding the /**/ pattern (e.g. by not putting a / before a wildcard) or using this feature only in directory subtrees which do not have many files that don't match the pattern (e.g. making a subdirectory for your JSON files and explicitly including that subdirectory in the pattern).

• Path aliases in tsconfig.json no longer count as packages (#​2792, #​3003, #​3160, #​3238)

  Setting --packages=external tells esbuild to make all import paths external when they look like a package path. For example, an import of ./foo/bar is not a package path and won't be external while an import of foo/bar is a package path and will be external. However, the paths field in tsconfig.json allows you to create import paths that look like package paths but that do not resolve to packages. People do not want these paths to count as package paths. So with this release, the behavior of --packages=external has been changed to happen after the tsconfig.json path remapping step.

• Use the local-css loader for .module.css files by default (#​20)

  With this release the css loader is still used for .css files except that .module.css files now use the local-css loader. This is a common convention in the web development community. If you need .module.css files to use the css loader instead, then you can override this behavior with --loader:.module.css=css.

v0.18.20

Compare Source

• Support advanced CSS @import rules (#​953, #​3137)

  CSS @import statements have been extended to allow additional trailing tokens after the import path. These tokens sort of make the imported file behave as if it were wrapped in a @layer, @supports, and/or @media rule. Here are some examples:

  @​import url(foo.css);
  @​import url(foo.css) layer;
  @​import url(foo.css) layer(bar);
  @​import url(foo.css) layer(bar) supports(display: flex);
  @​import url(foo.css) layer(bar) supports(display: flex) print;
  @​import url(foo.css) layer(bar) print;
  @​import url(foo.css) supports(display: flex);
  @​import url(foo.css) supports(display: flex) print;
  @​import url(foo.css) print;

  You can read more about this advanced syntax here. With this release, esbuild will now bundle @import rules with these trailing tokens and will wrap the imported files in the corresponding rules. Note that this now means a given imported file can potentially appear in multiple places in the bundle. However, esbuild will still only load it once (e.g. on-load plugins will only run once per file, not once per import).

v0.18.19

Compare Source

• Implement composes from CSS modules (#​20)

  This release implements the composes annotation from the CSS modules specification. It provides a way for class selectors to reference other class selectors (assuming you are using the local-css loader). And with the from syntax, this can even work with local names across CSS files. For example:

  // app.js
  import { submit } from './style.css'
  const div = document.createElement('div')
  div.className = submit
  document.body.appendChild(div)

  /* style.css */
  .button {
    composes: pulse from "anim.css";
    display: inline-block;
  }
  .submit {
    composes: button;
    font-weight: bold;
  }

  /* anim.css */
  @​keyframes pulse {
    from, to { opacity: 1 }
    50% { opacity: 0.5 }
  }
  .pulse {
    animation: 2s ease-in-out infinite pulse;
  }

  Bundling this with esbuild using --bundle --outdir=dist --loader:.css=local-css now gives the following:

  (() => {
    // style.css
    var submit = "anim_pulse style_button style_submit";
  
    // app.js
    var div = document.createElement("div");
    div.className = submit;
    document.body.appendChild(div);
  })();

  /* anim.css */
  @​keyframes anim_pulse {
    from, to {
      opacity: 1;
    }
    50% {
      opacity: 0.5;
    }
  }
  .anim_pulse {
    animation: 2s ease-in-out infinite anim_pulse;
  }
  
  /* style.css */
  .style_button {
    display: inline-block;
  }
  .style_submit {
    font-weight: bold;
  }

  Import paths in the composes: ... from syntax are resolved using the new composes-from import kind, which can be intercepted by plugins during import path resolution when bundling is enabled.

  Note that the order in which composed CSS classes from separate files appear in the bundled output file is deliberately undefined by design (see the specification for details). You are not supposed to declare the same CSS property in two separate class selectors and then compose them together. You are only supposed to compose CSS class selectors that declare non-overlapping CSS properties.

  Issue #​20 (the issue tracking CSS modules) is esbuild's most-upvoted issue! With this change, I now consider esbuild's implementation of CSS modules to be complete. There are still improvements to make and there may also be bugs with the current implementation, but these can be tracked in separate issues.

• Fix non-determinism with tsconfig.json and symlinks (#​3284)

  This release fixes an issue that could cause esbuild to sometimes emit incorrect build output in cases where a file under the effect of tsconfig.json is inconsistently referenced through a symlink. It can happen when using npm link to create a symlink within node_modules to an unpublished package. The build result was non-deterministic because esbuild runs module resolution in parallel and the result of the tsconfig.json lookup depended on whether the import through the symlink or not through the symlink was resolved first. This problem was fixed by moving the realpath operation before the tsconfig.json lookup.

• Add a hash property to output files (#​3084, #​3293)

  As a convenience, every output file in esbuild's API now includes a hash property that is a hash of the contents field. This is the hash that's used internally by esbuild to detect changes between builds for esbuild's live-reload feature. You may also use it to detect changes between your own builds if its properties are sufficient for your use case.

  This feature has been added directly to output file objects since it's just a hash of the contents field, so it makes conceptual sense to store it in the same location. Another benefit of putting it there instead of including it as a part of the watch mode API is that it can be used without watch mode enabled. You can use it to compare the output of two independent builds that were done at different times.

  The hash algorithm (currently XXH64) is implementation-dependent and may be changed at any time in between esbuild versions. If you don't like esbuild's choice of hash algorithm then you are welcome to hash the contents yourself instead. As with any hash algorithm, note that while two different hashes mean that the contents are different, two equal hashes do not necessarily mean that the contents are equal. You may still want to compare the contents in addition to the hashes to detect with certainty when output files have been changed.

• Avoid generating duplicate prefixed declarations in CSS (#​3292)

  There was a request for esbuild's CSS prefixer to avoid generating a prefixed declaration if a declaration by that name is already present in the same rule block. So with this release, esbuild will now avoid doing this:

  /* Original code */
  body {
    backdrop-filter: blur(30px);
    -webkit-backdrop-filter: blur(45px);
  }
  
  /* Old output (with --target=safari12) */
  body {
    -webkit-backdrop-filter: blur(30px);
    backdrop-filter: blur(30px);
    -webkit-backdrop-filter: blur(45px);
  }
  
  /* New output (with --target=safari12) */
  body {
    backdrop-filter: blur(30px);
    -webkit-backdrop-filter: blur(45px);
  }

  This can result in a visual difference in certain cases (for example if the browser understands blur(30px) but not blur(45px), it will be able to fall back to blur(30px)). But this change means esbuild now matches the behavior of Autoprefixer which is probably a good representation of how people expect this feature to work.

v0.18.18

Compare Source

• Fix asset references with the --line-limit flag (#​3286)

  The recently-released --line-limit flag tells esbuild to terminate long lines after they pass this length limit. This includes automatically wrapping long strings across multiple lines using escaped newline syntax. However, using this could cause esbuild to generate incorrect code for references from generated output files to assets in the bundle (i.e. files loaded with the file or copy loaders). This is because esbuild implements asset references internally using find-and-replace with a randomly-generated string, but the find operation fails if the string is split by an escaped newline due to line wrapping. This release fixes the problem by not wrapping these strings. This issue affected asset references in both JS and CSS files.

• Support local names in CSS for @keyframe, @counter-style, and @container (#​20)

  This release extends support for local names in CSS files loaded with the local-css loader to cover the @keyframe, @counter-style, and @container rules (and also animation, list-style, and container declarations). Here's an example:

  @​keyframes pulse {
    from, to { opacity: 1 }
    50% { opacity: 0.5 }
  }
  @​counter-style moon {
    system: cyclic;
    symbols: 🌕 🌖 🌗 🌘 🌑 🌒 🌓 🌔;
  }
  @​container squish {
    li { float: left }
  }
  ul {
    animation: 2s ease-in-out infinite pulse;
    list-style: inside moon;
    container: squish / size;
  }

  With the local-css loader enabled, that CSS will be turned into something like this (with the local name mapping exposed to JS):

  @​keyframes stdin_pulse {
    from, to {
      opacity: 1;
    }
    50% {
      opacity: 0.5;
    }
  }
  @​counter-style stdin_moon {
    system: cyclic;
    symbols: 🌕 🌖 🌗 🌘 🌑 🌒 🌓 🌔;
  }
  @​container stdin_squish {
    li {
      float: left;
    }
  }
  ul {
    animation: 2s ease-in-out infinite stdin_pulse;
    list-style: inside stdin_moon;
    container: stdin_squish / size;
  }

  If you want to use a global name within a file loaded with the local-css loader, you can use a :global selector to do that:

  div {
    /* All symbols are global inside this scope (i.e.
     * "pulse", "moon", and "squish" are global below) */
    :global {
      animation: 2s ease-in-out infinite pulse;
      list-style: inside moon;
      container: squish / size;
    }
  }

  If you want to use @keyframes, @counter-style, or @container with a global name, make sure it's in a file that uses the css or global-css loader instead of the local-css loader. For example, you can configure --loader:.module.css=local-css so that the local-css loader only applies to *.module.css files.

• Support strings as keyframe animation names in CSS (#​2555)

  With this release, esbuild will now parse animation names that are specified as strings and will convert them to identifiers. The CSS specification allows animation names to be specified using either identifiers or strings but Chrome only understands identifiers, so esbuild will now always convert string names to identifier names for Chrome compatibility:

  /* Original code */
  @​keyframes "hide menu" {
    from { opacity: 1 }
    to { opacity: 0 }
  }
  menu.hide {
    animation: 0.5s ease-in-out "hide menu";
  }
  
  /* Old output */
  @​keyframes "hide menu" { from { opacity: 1 } to { opacity: 0 } }
  menu.hide {
    animation: 0.5s ease-in-out "hide menu";
  }
  
  /* New output */
  @​keyframes hide\ menu {
    from {
      opacity: 1;
    }
    to {
      opacity: 0;
    }
  }
  menu.hide {
    animation: 0.5s ease-in-out hide\ menu;
  }

v0.18.17

Compare Source

• Support An+B syntax and :nth-*() pseudo-classes in CSS

  This adds support for the :nth-child(), :nth-last-child(), :nth-of-type(), and :nth-last-of-type() pseudo-classes to esbuild, which has the following consequences:

  • The An+B syntax is now parsed, so parse errors are now reported
  • An+B values inside these pseudo-classes are now pretty-printed (e.g. a leading + will be stripped because it's not in the AST)
  • When minification is enabled, An+B values are reduced to equivalent but shorter forms (e.g. 2n+0 => 2n, 2n+1 => odd)
  • Local CSS names in an of clause are now detected (e.g. in :nth-child(2n of :local(.foo)) the name foo is now renamed)

  /* Original code */
  .foo:nth-child(+2n+1 of :local(.bar)) {
    color: red;
  }
  
  /* Old output (with --loader=local-css) */
  .stdin_foo:nth-child(+2n + 1 of :local(.bar)) {
    color: red;
  }
  
  /* New output (with --loader=local-css) */
  .stdin_foo:nth-child(2n+1 of .stdin_bar) {
    color: red;
  }

• Adjust CSS nesting parser for IE7 hacks (#​3272)

  This fixes a regression with esbuild's treatment of IE7 hacks in CSS. CSS nesting allows selectors to be used where declarations are expected. There's an IE7 hack where prefixing a declaration with a * causes that declaration to only be applied in IE7 due to a bug in IE7's CSS parser. However, it's valid for nested CSS selectors to start with *. So esbuild was incorrectly parsing these declarations and anything following it up until the next { as a selector for a nested CSS rule. This release changes esbuild's parser to terminate the parsing of selectors for nested CSS rules when a ; is encountered to fix this edge case:

  /* Original code */
  .item {
    *width: 100%;
    height: 1px;
  }
  
  /* Old output */
  .item {
    *width: 100%; height: 1px; {
    }
  }
  
  /* New output */
  .item {
    *width: 100%;
    height: 1px;
  }

  Note that the syntax for CSS nesting is about to change again, so esbuild's CSS parser may still not be completely accurate with how browsers do and/or will interpret CSS nesting syntax. Expect additional updates to esbuild's CSS parser in the future to deal with upcoming CSS specification changes.

• Adjust esbuild's warning about undefined imports for TypeScript import equals declarations (#​3271)

  In JavaScript, accessing a missing property on an import namespace object is supposed to result in a value of undefined at run-time instead of an error at compile-time. This is something that esbuild warns you about by default because doing this can indicate a bug with your code. For example:

  // app.js
  import * as styles from './styles'
  console.log(styles.buton)

  // styles.js
  export let button = {}

  If you bundle app.js with esbuild you will get this:

  ▲ [WARNING] Import "buton" will always be undefined because there is no matching export in "styles.js" [import-is-undefined]
  
      app.js:2:19:
        2 │ console.log(styles.buton)
          │                    ~~~~~
          ╵                    button
  
    Did you mean to import "button" instead?
  
      styles.js:1:11:
        1 │ export let button = {}
          ╵            ~~~~~~
  

  However, there is TypeScript-only syntax for import equals declarations that can represent either a type import (which esbuild should ignore) or a value import (which esbuild should respect). Since esbuild doesn't have a type system, it tries to only respect import equals declarations that are actually used as values. Previously esbuild always generated this warning for unused imports referenced within import equals declarations even when the reference could be a type instead of a value. Starting with this release, esbuild will now only warn in this case if the import is actually used. Here is an example of some code that no longer causes an incorrect warning:

  // app.ts
  import * as styles from './styles'
  import ButtonType = styles.Button

  // styles.ts
  export interface Button {}

v0.18.16

Compare Source

• Fix a regression with whitespace inside :is() (#​3265)

  The change to parse the contents of :is() in version 0.18.14 introduced a regression that incorrectly flagged the contents as a syntax error if the contents started with a whitespace token (for example div:is( .foo ) {}). This regression has been fixed.

v0.18.15

Compare Source

• Add the --serve-fallback= option (#​2904)

  The web server built into esbuild serves the latest in-memory results of the configured build. If the requested path doesn't match any in-memory build result, esbuild also provides the --servedir= option to tell esbuild to serve the requested path from that directory instead. And if the requested path doesn't match either of those things, esbuild will either automatically generate a directory listing (for directories) or return a 404 error.

  Starting with this release, that last step can now be replaced with telling esbuild to serve a specific HTML file using the --serve-fallback= option. This can be used to provide a "not found" page for missing URLs. It can also be used to implement a single-page app that mutates the current URL and therefore requires the single app entry point to be served when the page is loaded regardless of whatever the current URL is.

• Use the tsconfig field in package.json during extends resolution (#​3247)

  This release adds a feature from TypeScript 3.2 where if a tsconfig.json file specifies a package name in the extends field and that package's package.json file has a tsconfig field, the contents of that field are used in the search for the base tsconfig.json file.

• Implement CSS nesting without :is() when possible (#​1945)

  Previously esbuild would always produce a warning when transforming nested CSS for a browser that doesn't support the :is() pseudo-class. This was because the nesting transform needs to generate an :is() in some complex cases which means the transformed CSS would then not work in that browser. However, the CSS nesting transform can often be done without generating an :is(). So with this release, esbuild will no longer warn when targeting browsers that don't support :is() in the cases where an :is() isn't needed to represent the nested CSS.

  In addition, esbuild's nested CSS transform has been updated to avoid generating an :is() in cases where an :is() is preferable but there's a longer alternative that is also equivalent. This update means esbuild can now generate a combinatorial explosion of CSS for complex CSS nesting syntax when targeting browsers that don't support :is(). This combinatorial explosion is necessary to accurately represent the original semantics. For example:

  /* Original code */
  .first,
  .second,
  .third {
    & > & {
      color: red;
    }
  }
  
  /* Old output (with --target=chrome80) */
  :is(.first, .second, .third) > :is(.first, .second, .third) {
    color: red;
  }
  
  /* New output (with --target=chrome80) */
  .first > .first,
  .first > .second,
  .first > .third,
  .second > .first,
  .second > .second,
  .second > .third,
  .third > .first,
  .third > .second,
  .third > .third {
    color: red;
  }

  This change means you can now use CSS nesting with esbuild when targeting an older browser that doesn't support :is(). You'll now only get a warning from esbuild if you use complex CSS nesting syntax that esbuild can't represent in that older browser without using :is(). There are two such cases:

  /* Case 1 */
  a b {
    .foo & {
      color: red;
    }
  }
  
  /* Case 2 */
  a {
    > b& {
      color: red;
    }
  }

  These two cases still need to use :is(), both for different reasons, and cannot be used when targeting an older browser that doesn't support :is():

  /* Case 1 */
  .foo :is(a b) {
    color: red;
  }
  
  /* Case 2 */
  a > a:is(b) {
    color: red;
  }

• Automatically lower inset in CSS for older browsers

  With this release, esbuild will now automatically expand the inset property to the top, right, bottom, and left properties when esbuild's target is set to a browser that doesn't support inset:

  /* Original code */
  .app {
    position: absolute;
    inset: 10px 20px;
  }
  
  /* Old output (with --target=chrome80) */
  .app {
    position: absolute;
    inset: 10px 20px;
  }
  
  /* New output (with --target=chrome80) */
  .app {
    position: absolute;
    top: 10px;
    right: 20px;
    bottom: 10px;
    left: 20px;
  }

• Add support for the new @starting-style CSS rule (#​3249)

  This at rule allow authors to start CSS transitions on first style update. That is, you can now make the transition take effect when the display property changes from none to block.

  /* Original code */
  @​starting-style {
    h1 {
      background-color: transparent;
    }
  }
  
  /* Output */
  @​starting-style{h1{background-color:transparent}}

  This was contributed by @​yisibl.

v0.18.14

Compare Source

• Implement local CSS names (#​20)

  This release introduces two new loaders called global-css and local-css and two new pseudo-class selectors :local() and :global(). This is a partial implementation of the popular CSS modules approach for avoiding unintentional name collisions in CSS. I'm not calling this feature "CSS modules" because although some people in the community call it that, other people in the community have started using "CSS modules" to refer to something completely different and now CSS modules is an overloaded term.

  Here's how this new local CSS name feature works with esbuild:

  • Identifiers that look like .className and #idName are global with the global-css loader and local with the local-css loader. Global identifiers are the same across all files (the way CSS normally works) but local identifiers are different between different files. If two separate CSS files use the same local identifier .button, esbuild will automatically rename one of them so that they don't collide. This is analogous to how esbuild automatically renames JS local variables with the same name in separate JS files to avoid name collisions.

  • It only makes sense to use local CSS names with esbuild when you are also using esbuild's bundler to bundle JS files that import CSS files. When you do that, esbuild will generate one export for each local name in the CSS file. The JS code can import these names and use them when constructing HTML DOM. For example:

    // app.js
    import { outerShell } from './app.css'
    const div = document.createElement('div')
    div.className = outerShell
    document.body.appendChild(div)

    /* app.css */
    .outerShell {
      position: absolute;
      inset: 0;
    }

    When you bundle this with esbuild app.js --bundle --loader:.css=local-css --outdir=out you'll now get this (notice how the local CSS name outerShell has been renamed):

    // out/app.js
    (() => {
      // app.css
      var outerShell = "app_outerShell";
    
      // app.js
      var div = document.createElement("div");
      div.className = outerShell;
      document.body.appendChild(div);
    })();

    /* out/app.css */
    .app_outerShell {
      position: absolute;
      inset: 0;
    }

    This feature only makes sense to use when bundling is enabled both because your code needs to import the renamed local names so that it can use them, and because esbuild needs to be able to process all CSS files containing local names in a single bundling operation so that it can successfully rename conflicting local names to avoid collisions.

  • If you are in a global CSS file (with the global-css loader) you can create a local name using :local(), and if you are in a local CSS file (with the local-css loader) you can create a global name with :global(). So the choice of the global-css loader vs. the local-css loader just sets the default behavior for identifiers, but you can override it on a case-by-case basis as necessary. For example:

    :local(.button) {
      color: red;
    }
    :global(.button) {
      color: blue;
    }

    Processing this CSS file with esbuild with either the global-css or local-css loader will result in something like this:

    .stdin_button {
      color: red;
    }
    .button {
      color: blue;
    }

  • The names that esbuild generates for local CSS names are an implementation detail and are not intended to be hard-coded anywhere. The only way you should be referencing the local CSS names in your JS or HTML is with an import statement in JS that is bundled with esbuild, as demonstrated above. For example, when --minify is enabled esbuild will use a different name generation algorithm which generates names that are as short as possible (analogous to how esbuild minifies local identifiers in JS).

  • You can easily use both global CSS files and local CSS files simultaneously if you give them different file extensions. For example, you could pass --loader:.css=global-css and --loader:.module.css=local-css to esbuild so that .css files still use global names by default but .module.css files use local names by default.

  • Keep in mind that the css loader is different than the global-css loader. The :local and :global annotations are not enabled with the css loader and will be passed through unchanged. This allows you to have the option of using esbuild to process CSS containing while preserving these annotations. It also means that local CSS names are disabled by default for now (since the css loader is currently the default for CSS files). The :local and :global syntax may be enabled by default in a future release.

  Note that esbuild's implementation does not currently have feature parity with other implementations of modular CSS in similar tools. This is only a preliminary release with a partial implementation that includes some basic behavior to get the process started. Additional behavior may be added in future releases. In particular, this release does not implement:

  • The composes pragma
  • Tree shaking for unused local CSS
  • Local names for keyframe animations, grid lines, @container, @counter-style, etc.

  Issue #​20 (the issue for this feature) is esbuild's most-upvoted issue! While this release still leaves that issue open, it's an important first step in that direction.

• Parse :is, :has, :not, and :where in CSS

  With this release, esbuild will now parse the contents of these pseudo-class selectors as a selector list. This means you will now get syntax warnings within these selectors for invalid selector syntax. It also means that esbuild's CSS nesting transform behaves slightly differently than before because esbuild is now operating on an AST instead of a token stream. For example:

  /* Original code */
  div {
    :where(.foo&) {
      color: red;
    }
  }
  
  /* Old output (with --target=chrome90) */
  :where(.foo:is(div)) {
    color: red;
  }
  
  /* New output (with --target=chrome90) */
  :where(div.foo) {
    color: red;
  }

v0.18.13

Compare Source

• Add the --drop-labels= option (#​2398)

  If you want to conditionally disable some development-only code and have it not be present in the final production bundle, right now the most straightforward way of doing this is to use the --define: flag along with a specially-named global variable. For example, consider the following code:

  function main() {
    DEV && doAnExpensiveCheck()
  }

  You can build this for development and production like this:

  • Development: esbuild --define:DEV=true
  • Production: esbuild --define:DEV=false

  One drawback of this approach is that the resulting code crashes if you don't provide a value for DEV with --define:. In practice this isn't that big of a problem, and there are also various ways to work around this.

  However, another approach that avoids this drawback is to use JavaScript label statements instead. That's what the --drop-labels= flag implements. For example, consider the following code:

  function main() {
    DEV: doAnExpensiveCheck()
  }

  With this release, you can now build this for development and production like this:

  • Development: esbuild
  • Production: esbuild --drop-labels=DEV

  This means that code containing optional development-only checks can now be written such that it's safe to run without any additional configuration. The --drop-labels= flag takes comma-separated list of multiple label names to drop.

• Avoid causing unhandledRejection during shutdown (#​3219)

  All pending esbuild JavaScript API calls are supposed to fail if esbuild's underlying child process is unexpectedly terminated. This can happen if SIGINT is sent to the parent node process with Ctrl+C, for example. Previously doing this could also cause an unhandled promise rejection when esbuild attempted to communicate this failure to its own child process that no longer exists. This release now swallows this communication failure, which should prevent this internal unhandled promise rejection. This change means that you can now use esbuild's JavaScript API with a custom SIGINT handler that extends the lifetime of the node process without esbuild's internals causing an early exit due to an unhandled promise rejection.

• Update browser compatibility table scripts

  The scripts that esbuild uses to compile its internal browser compatibility table have been overhauled. Briefly:

  • Converted from JavaScript to TypeScript
  • Fixed some bugs that resulted in small changes to the table
  • Added caniuse-lite and @mdn/browser-compat-data as new data sources (replacing manually-copied information)

  This change means it's now much easier to keep esbuild's internal compatibility tables up to date. You can review the table changes here if you need to debug something about this change:

  • JS table changes
  • CSS table changes

v0.18.12

Compare Source

• Fix a panic with const enum inside parentheses (#​3205)

  This release fixes an edge case where esbuild could potentially panic if a TypeScript const enum statement was used inside of a parenthesized expression and was followed by certain other scope-related statements. Here's a minimal example that triggers this edge case:

  (() => {
    const enum E { a };
    () => E.a
  })

• Allow a newline in the middle of TypeScript export type statement (#​3225)

  Previously esbuild incorrectly rejected the following valid TypeScript code:

  export type
  { T };
  
  export type
  * as foo from 'bar';

  Code that uses a newline after export type is now allowed starting with this release.

• Fix cross-module inlining of string enums (#​3210)

  A refactoring typo in version 0.18.9 accidentally introduced a regression with cross-module inlining of string enums when combined with computed property accesses. This regression has been fixed.

• Rewrite .js to .ts inside packages with exports (#​3201)

  Packages with the exports field are supposed to disable node's path resolution behavior that allows you to import a file with a different extension than the one in the source code (for example, importing foo/bar to get foo/bar.js). And TypeScript has behavior where you can import a non-existent .js file and you will get the .ts file instead. Previously the presence of the exports field caused esbuild to disable all extension manipulation stuff which included both node's implicit file extension searching and TypeScript's file extension swapping. However, TypeScript appears to always apply file extension swapping even in this case. So with this release, esbuild will now rewrite .js to .ts even inside packages with exports.

• Fix a redirect edge case in esbuild's development server (#​3208)

  The development server canonicalizes directory URLs by adding a trailing slash. For example, visiting /about redirects to /about/ if /about/index.html would be served. However, if the requested path begins with two slashes, then the redirect incorrectly turned into a protocol-relative URL. For example, visiting //about redirected to //about/ which the browser turns into http://about/. This release fixes the bug by canonicalizing the URL path when doing this redirect.

v0.18.11

Compare Source

• Fix a TypeScript code generation edge case (#​3199)

  This release fixes a regression in version 0.18.4 where using a TypeScript namespace that exports a class declaration combined with --keep-names and a --target of es2021 or earlier could cause esbuild to export the class from the namespace using an incorrect name (notice the assignment to X2._Y vs. X2.Y):

  // Original code
  
  // Old output (with --keep-names --target=es2021)
  var X;
  ((X2) => {
    const _Y = class _Y {
    };
    __name(_Y, "Y");
    let Y = _Y;
    X2._Y = _Y;
  })(X || (X = {}));
  
  // New output (with --keep-names --target=es2021)
  var X;
  ((X2) => {
    const _Y = class _Y {
    };
    __name(_Y, "Y");
    let Y = _Y;
    X2.Y = _Y;
  })(X || (X = {}));

v0.18.10

Compare Source

• Fix a tree-shaking bug that removed side effects (#​3195)

  This fixes a regression in version 0.18.4 where combining --minify-syntax with --keep-names could cause expressions with side effects after a function declaration to be considered side-effect free for tree shaking purposes. The reason was because --keep-names generates an expression statement containing a call to a helper function after the function declaration with a special flag that makes the function call able to be tree shaken, and then --minify-syntax could potentially merge that expression statement with following expressions without clearing the flag. This release fixes the bug by clearing the flag when merging expression statements together.

• Fix an incorrect warning about CSS nesting (#​3197)

  A warning is currently generated when transforming nested CSS to a browser that doesn't support :is() because transformed nested CSS may need to use that feature to represent nesting. This was previously always triggered when an at-rule was encountered in a declaration context. Typically the only case you would encounter this is when using CSS nesting within a selector rule. However, there is a case where that's not true: when using a margin at-rule such as @top-left within @page. This release avoids incorrectly generating a warning in this case by checking that the at-rule is within a selector rule before generating a warning.

v0.18.9

Compare Source

• Fix await using declarations inside async generator functions

  I forgot about the new await using declarations when implementing lowering for async generator functions in the previous release. This change fixes the transformation of await using declarations when they are inside lowered async generator functions:

  // Original code
  async function* foo() {
    await using x = await y
  }
  
  // Old output (with --supported:async-generator=false)
  function foo() {
    return __asyncGenerator(this, null, function* () {
      await using x = yield new __await(y);
    });
  }
  
  // New output (with --supported:async-generator=false)
  function foo() {
    return __asyncGenerator(this, null, function* () {
      var _stack = [];
      try {
        const x = __using(_stack, yield new __await(y), true);
      } catch (_) {
        var _error = _, _hasError = true;
      } finally {
        var _promise = __callDispose(_stack, _error, _hasError);
        _promise && (yield new __await(_promise));
      }
    });
  }

• Insert some prefixed CSS properties when appropriate (#​3122)

  With this release, esbuild will now insert prefixed CSS properties in certain cases when the target setting includes browsers that require a certain prefix. This is currently done for the following properties:

  • appearance: *; => -webkit-appearance: *; -moz-appearance: *;
  • backdrop-filter: *; => -webkit-backdrop-filter: *;
  • background-clip: text => -webkit-background-clip: text;
  • box-decoration-break: *; => -webkit-box-decoration-break: *;
  • clip-path: *; => -webkit-clip-path: *;
  • font-kerning: *; => -webkit-font-kerning: *;
  • hyphens: *; => -webkit-hyphens: *;
  • initial-letter: *; => -webkit-initial-letter: *;
  • mask-image: *; => -webkit-mask-image: *;
  • mask-origin: *; => -webkit-mask-origin: *;
  • mask-position: *; => -webkit-mask-position: *;
  • mask-repeat: *; => -webkit-mask-repeat: *;
  • mask-size: *; => -webkit-mask-size: *;
  • position: sticky; => position: -webkit-sticky;
  • print-color-adjust: *; => -webkit-print-color-adjust: *;
  • tab-size: *; => -moz-tab-size: *; -o-tab-size: *;
  • text-decoration-color: *; => -webkit-text-decoration-color: *; -moz-text-decoration-color: *;
  • text-decoration-line: *; => -webkit-text-decoration-line: *; -moz-text-decoration-line: *;
  • text-decoration-skip: *; => -webkit-text-decoration-skip: *;
  • text-emphasis-color: *; => -webkit-text-emphasis-color: *;
  • text-emphasis-position: *; => -webkit-text-emphasis-position: *;
  • text-emphasis-style: *; => -webkit-text-emphasis-style: *;
  • text-orientation: *; => `-webkit-text-orientation: *

---

Configuration

📅 Schedule: Branch creation - "every weekend" (UTC), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• If you want to rebase/retry this PR, check this box

---

This PR has been generated by Mend Renovate. View repository job log here.

[codecov]

Codecov Report

Merging #616 (5bd65e4) into main (1a2ce57) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main      #616   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            4         4           
  Lines          405       405           
  Branches        56        56           
=========================================
  Hits           405       405