v0.18.13

• 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