esbuild rules for Bazel
The esbuild rules runs the esbuild bundler tool with Bazel. esbuild is an extremely fast JavaScript bundler written in Go, its current benchmarks show it can be 320x faster that other bundlers
Installation
Add the @bazel/esbuild
npm packages to your devDependencies
in package.json
.
npm install --save-dev @bazel/esbuild
or using yarn
yarn add -D @bazel/esbuild
Add an http_archive
fetching the esbuild binary for each platform that you need to support.
_ESBUILD_VERSION = "0.12.1" # reminder: update SHAs below when changing this value
http_archive(
name = "esbuild_darwin",
urls = [
"https://registry.npmjs.org/esbuild-darwin-64/-/esbuild-darwin-64-%s.tgz" % _ESBUILD_VERSION,
],
strip_prefix = "package",
build_file_content = """exports_files(["bin/esbuild"])""",
sha256 = "efb34692bfa34db61139eb8e46cd6cf767a42048f41c8108267279aaf58a948f",
)
http_archive(
name = "esbuild_windows",
urls = [
"https://registry.npmjs.org/esbuild-windows-64/-/esbuild-windows-64-%s.tgz" % _ESBUILD_VERSION,
],
strip_prefix = "package",
build_file_content = """exports_files(["esbuild.exe"])""",
sha256 = "10439647b11c7fd1d9647fd98d022fe2188b4877d2d0b4acbe857f4e764b17a9",
)
http_archive(
name = "esbuild_linux",
urls = [
"https://registry.npmjs.org/esbuild-linux-64/-/esbuild-linux-64-%s.tgz" % _ESBUILD_VERSION,
],
strip_prefix = "package",
build_file_content = """exports_files(["bin/esbuild"])""",
sha256 = "de8409b90ec3c018ffd899b49ed5fc462c61b8c702ea0f9da013e0e1cd71549a",
)
These can then be referenced on the tool
attribute of the esbuild
rule.
esbuild(
name = "bundle",
...
tool = select({
"@bazel_tools//src/conditions:darwin": "@esbuild_darwin//:bin/esbuild",
"@bazel_tools//src/conditions:windows": "@esbuild_windows//:esbuild.exe",
"@bazel_tools//src/conditions:linux_x86_64": "@esbuild_linux//:bin/esbuild",
}),
)
It might be useful to wrap this locally in a macro for better reuseability, see packages/esbuild/test/tests.bzl
for an example.
The esbuild
rule can take a JS or TS dependency tree and bundle it to a single file, or split across multiple files, outputting a directory.
load("//packages/esbuild:index.bzl", "esbuild")
load("//packages/typescript:index.bzl", "ts_library")
ts_library(
name = "lib",
srcs = ["a.ts"],
)
esbuild(
name = "bundle",
entry_point = "a.ts",
deps = [":lib"],
)
The above will create three output files, bundle.js
, bundle.js.map
and bundle_metadata.json
which contains the bundle metadata to aid in debugging and resoloution tracing.
To create a code split bundle, set splitting = True
on the esbuild
rule.
load("//packages/esbuild:index.bzl", "esbuild")
load("//packages/typescript:index.bzl", "ts_library")
ts_library(
name = "lib",
srcs = ["a.ts"],
deps = [
"@npm//foo",
],
)
esbuild(
name = "bundle",
entry_point = "a.ts",
deps = [":lib"],
splitting = True,
)
This will create an output directory containing all the code split chunks, along with their sourcemaps files
Rules
esbuild
Runs the esbuild bundler under Bazel
For further information about esbuild, see https://esbuild.github.io/
Example usage (generated)
load("@npm//@bazel/esbuild:index.bzl", "esbuild")
esbuild(
# A unique name for this target.
name = "",
# Internal use only
launcher = "",
# An executable for the esbuild binary
tool = "",
)
name
A unique name for this target.
args
A list of extra arguments that are included in the call to esbuild. $(location ...) can be used to resolve the path to a Bazel target.
define
A list of global identifier replacements. Example:
esbuild(
name = "bundle",
define = [
"process.env.NODE_ENV=\"production\""
],
)
See https://esbuild.github.io/api/#define for more details
deps
A list of direct dependencies that are required to build the bundle
entry_point
The bundle's entry point (e.g. your main.js or app.js or index.js)
This is a shortcut for the entry_points
attribute with a single entry.
Specify either this attribute or entry_point
, but not both.
entry_points
The bundle's entry points (e.g. your main.js or app.js or index.js)
Specify either this attribute or entry_point
, but not both.
external
A list of module names that are treated as external and not included in the resulting bundle
See https://esbuild.github.io/api/#external for more details
format
The output format of the bundle, defaults to iife when platform is browser and cjs when platform is node. If performing code splitting or multiple entry_points are specified, defaults to esm.
See https://esbuild.github.io/api/#format for more details
launcher
Internal use only
link_workspace_root
Link the workspace root to the bin_dir to support absolute requires like 'my_wksp/path/to/file'. If source files need to be required then they can be copied to the bin_dir with copy_to_bin.
max_threads
Sets the GOMAXPROCS
variable to limit the number of threads that esbuild can run with.
This can be useful if running many esbuild rule invocations in parallel, which has the potential to cause slowdown.
For general use, leave this attribute unset.
minify
Minifies the bundle with the built in minification. Removes whitespace, shortens identifieres and uses equivalent but shorter syntax.
Sets all --minify-* flags
See https://esbuild.github.io/api/#minify for more details
output
Name of the output file when bundling
output_css
Declare a .css file will be output next to output bundle.
If your JS code contains import statements that import .css files, esbuild will place the content in a file next to the main output file, which you'll need to declare. If your output file is named 'foo.js', you should set this to 'foo.css'.
output_dir
If true, esbuild produces an output directory containing all the output files from code splitting for multiple entry points
See https://esbuild.github.io/api/#splitting and https://esbuild.github.io/api/#entry-points for more details
output_map
Name of the output source map when bundling
platform
The platform to bundle for.
See https://esbuild.github.io/api/#platform for more details
sourcemap
Defines where sourcemaps are output and how they are included in the bundle. By default, a separate .js.map
file is generated and referenced by the bundle. If 'external', a separate .js.map
file is generated but not referenced by the bundle. If 'inline', a sourcemap is generated and its contents are inlined into the bundle (and no external sourcemap file is created). If 'both', a sourcemap is inlined and a .js.map
file is created.
See https://esbuild.github.io/api/#sourcemap for more details
sources_content
If False, omits the sourcesContent
field from generated source maps
See https://esbuild.github.io/api/#sources-content for more details
srcs
Source files to be made available to esbuild
target
Environment target (e.g. es2017, chrome58, firefox57, safari11, edge16, node10, esnext). Default es2015.
See https://esbuild.github.io/api/#target for more details
tool
An executable for the esbuild binary