Changelog: 2022

This changelog documents all esbuild versions published in the year 2022 (versions 0.14.11 through 0.16.12).

0.16.12

• Loader defaults to js for extensionless files (#2776)

  Certain packages contain files without an extension. For example, the yargs package contains the file yargs/yargs which has no extension. Node, Webpack, and Parcel can all understand code that imports yargs/yargs because they assume that the file is JavaScript. However, esbuild was previously unable to understand this code because it relies on the file extension to tell it how to interpret the file. With this release, esbuild will now assume files without an extension are JavaScript files. This can be customized by setting the loader for "" (the empty string, representing files without an extension) to another loader. For example, if you want files without an extension to be treated as CSS instead, you can do that like this:

  • CLI:

    esbuild --bundle --loader:=css
    

  • JS:

    esbuild.build({
      bundle: true,
      loader: { '': 'css' },
    })

  • Go:

    api.Build(api.BuildOptions{
      Bundle: true,
      Loader: map[string]api.Loader{"": api.LoaderCSS},
    })

  In addition, the "type" field in package.json files now only applies to files with an explicit .js, .jsx, .ts, or .tsx extension. Previously it was incorrectly applied by esbuild to all files that had an extension other than .mjs, .mts, .cjs, or .cts including extensionless files. So for example an extensionless file in a "type": "module" package is now treated as CommonJS instead of ESM.

0.16.11

• Avoid a syntax error in the presence of direct eval (#2761)

  The behavior of nested function declarations in JavaScript depends on whether the code is run in strict mode or not. It would be problematic if esbuild preserved nested function declarations in its output because then the behavior would depend on whether the output was run in strict mode or not instead of respecting the strict mode behavior of the original source code. To avoid this, esbuild transforms nested function declarations to preserve the intended behavior of the original source code regardless of whether the output is run in strict mode or not:

  // Original code
  if (true) {
    function foo() {}
    console.log(!!foo)
    foo = null
    console.log(!!foo)
  }