Bazel rules for esbuild
This is a Bazel rule which wraps the esbuild CLI.
Features:
- Same API as the
@bazel/esbuild
package, so it's easy to migrate. - Use the Bazel downloader to fetch the npm package and the native binaries as described here:
https://esbuild.github.io/getting-started/#download-a-build.
This means that the toolchain is fully self-contained and hermetic, and doesn't require you to
put esbuild in your package.json. These rules never run
npm install
.
Need help? This ruleset has support provided by https://aspect.dev.
Installation
From the release you wish to use:
https://github.com/aspect-build/rules_esbuild/releases
copy the WORKSPACE snippet into your WORKSPACE
file.
Usage
See the API documentation,
and the example usage in the examples/
directory.
Note that the examples rely on code in the /WORKSPACE
file in the root of this repo.
From a BUILD file
The simplest usage is with the esbuild
macro.
If needed, instead of the macro you could call the underlying esbuild_bundle
rule directly.
In a macro
You could write a Bazel macro which uses esbuild, by calling it from a genrule
or
run_binary
.
For this purpose, you can use the ESBUILD_BIN
Make variable exposed by the
@aspect_rules_esbuild//esbuild:resolved_toolchain
.
This is illustrated in examples/macro.
In a custom rule
The most advanced usage is to write your own custom rule.
This is a good choice if you need to integrate with other Bazel rules via Providers.
You can follow the example of /esbuild/defs.bzl
by re-using the lib
starlark struct exposed by
/esbuild/private/esbuild.bzl
.
Note that this is a private API which can change without notice.
Custom Toolchain
You can register your own toolchain to provide an esbuild binary. For example, you could build esbuild from source within the Bazel build, so that you can freely edit or patch esbuild and have those changes immediately reflected. You'll need these things:
- A rule which builds or loads an esbuild binary, for example a
go_binary
rule. - An
esbuild_toolchain
rule which depends on that binary from step 1 as thetarget_tool
. - A
toolchain
rule which depends on that target from step 2 as itstoolchain
and@aspect_rules_esbuild//esbuild:toolchain_type
as itstoolchain_type
. - A call to the
register_toolchains
function in yourWORKSPACE
that refers to thetoolchain
rule defined in step 3.