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
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
The esbuild binary is fetched automatically for your platform and is exposed via Bazel toolchains.
To do this, add the esbuild_repositories rule to your WORKSPACE.
You'll need to point it to the repository created by npm_install or yarn_install where the @bazel/esbuild
package is fetched. (Typically, this is npm).
Set the npm_repository attribute to the name of that repository.
npm_install(
name = "npm",
# @bazel/esbuild is a dependency in this package.json
package_json = "//:package.json",
package_lock_json = "//:package-lock.json",
)
load("@build_bazel_rules_nodejs//toolchains/esbuild:esbuild_repositories.bzl", "esbuild_repositories")
esbuild_repositories(npm_repository = "npm") # Note, npm is the default value for npm_repositoryTo avoid eagerly fetching all the npm dependencies, this load statement comes from the "Built-in"
@build_bazel_rules_nodejsrepository rather than from@npm. In rules_nodejs 5.0 we intend to fix this layering violation by having the whole esbuild support distributed independently of rules_nodejs, and not require any package to be installed from npm.
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("@npm//@bazel/esbuild:index.bzl", "esbuild")
load("@npm//@bazel/typescript:index.bzl", "ts_project")
ts_project(
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("@npm//@bazel/esbuild:index.bzl", "esbuild")
load("@npm//@bazel/typescript:index.bzl", "ts_project")
ts_project(
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
USAGE
esbuild(name, args, args_file, config, define, deps, entry_point, entry_points, external, format, launcher, link_workspace_root, max_threads, minify, node_context_data, output, output_css, output_dir, output_map, platform, sourcemap, sources_content, splitting, srcs, target)
Runs the esbuild bundler under Bazel
For further information about esbuild, see https://esbuild.github.io/
ATTRIBUTES
(Name, mandatory): A unique name for this target.
(Dictionary: String -> String): A dict of extra arguments that are included in the call to esbuild, where the key is the argument name. Values are subject to $(location ...) expansion
Defaults to {}
(Label): Internal use only
Defaults to None
(Label): Configuration file used for esbuild, from the esbuild_config macro. Note that options set in this file may get overwritten. See https://github.com/bazelbuild/rules_nodejs/tree/stable/packages/esbuild/test/plugins/BUILD.bazel for examples of using esbuild_config and plugins. The dependencies of this attribute must provide: Unknown Provider
Defaults to None
(Dictionary: String -> String): A dict of global identifier replacements. Values are subject to $(location ...) expansion. Example:
esbuild(
name = "bundle",
define = {
"process.env.NODE_ENV": "production"
},
)See https://esbuild.github.io/api/#define for more details
Defaults to {}
(List of labels): A list of direct dependencies that are required to build the bundle
Defaults to []
(Label): 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.
Defaults to None
(List of labels): 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.
Defaults to []
(List of strings): 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
Defaults to []
(String): 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
Defaults to ""
(Label, mandatory): Internal use only
(Boolean): 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.
Defaults to False
(Integer): 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.
Defaults to 0
(Boolean): 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
Defaults to False
(Label): Provides info about the build context, such as stamping.
By default it reads from the bazel command line, such as the --stamp argument.
Use this to override values for this target, such as enabling or disabling stamping.
You can use the node_context_data rule in @build_bazel_rules_nodejs//internal/node:context.bzl
to create a NodeContextInfo. The dependencies of this attribute must provide: NodeContextInfo
Defaults to @build_bazel_rules_nodejs//internal:node_context_data
(Label): Name of the output file when bundling
(Label): 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'.
(Boolean): If true, esbuild produces an output directory containing all output files
Defaults to False
(Label): Name of the output source map when bundling
(String): The platform to bundle for.
See https://esbuild.github.io/api/#platform for more details
Defaults to "browser"
(String): 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
Defaults to ""
(Boolean): If False, omits the sourcesContent field from generated source maps
See https://esbuild.github.io/api/#sources-content for more details
Defaults to False
(Boolean): 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
Defaults to False
(List of labels): Source files to be made available to esbuild
Defaults to []
(String): Environment target (e.g. es2017, chrome58, firefox57, safari11, edge16, node10, esnext). Default es2015.
See https://esbuild.github.io/api/#target for more details
Defaults to "es2015"
USAGE
configure_esbuild_toolchain(name, binary, exec_compatible_with)
Defines a toolchain for esbuild given the binary path and platform constraints
PARAMETERS
unique name for this toolchain, generally in the form "esbuild_platform_arch"
label for the esbuild binary
list of platform constraints
USAGE
esbuild_config(name, config_file, srcs, deps, kwargs)
Macro for an esbuild configuration file and its assoicated dependencies
PARAMETERS
Unique name for this rule
The configuration file / entrypoint
List of source files referenced by the configuration
Defaults to []
List of dependencies required for this configuration
Defaults to []
Any other common attributes
USAGE
esbuild_repositories(name, npm_repository)
Helper for fetching and setting up the esbuild versions and toolchains
PARAMETERS
currently unused
Defaults to ""
the name of the repository where the @bazel/esbuild package is installed by npm_install or yarn_install.
Defaults to "npm"