@bazel/terser

Terser rules for Bazel

WARNING: this is beta-quality software. Breaking changes are likely. Not recommended for production use without expert support.

The Terser rules run the Terser JS minifier with Bazel.

Wraps the Terser CLI documented at https://github.com/terser-js/terser#command-line-usage

Installation

Add the @bazel/terser npm package to your devDependencies in package.json.

Your WORKSPACE should declare a yarn_install or npm_install rule named npm. It should then install the rules found in the npm packages using the install_bazel_dependencies function. See https://github.com/bazelbuild/rules_nodejs/#quickstart

This causes the @bazel/terser package to be installed as a Bazel workspace named npm_bazel_terser.

Installing with self-managed dependencies

If you didn't use the yarn_install or npm_install rule to create an npm workspace, you'll have to declare a rule in your root BUILD.bazel file to execute terser:

# Create a terser rule to use in terser_minified#terser_bin
# attribute when using self-managed dependencies
nodejs_binary(
    name = "terser_bin",
    entry_point = "//:node_modules/terser/bin/uglifyjs",
    # Point bazel to your node_modules to find the entry point
    node_modules = ["//:node_modules"],
)

terser_minified

Run the terser minifier.

Typical example:

load("@npm_bazel_terser//:index.bzl", "terser_minified")

terser_minified(
    name = "out.min",
    src = "input.js",
    config_file = "terser_config.json",
)

Note that the name attribute determines what the resulting files will be called. So the example above will output out.min.js and out.min.js.map (since sourcemap defaults to true). If the input is a directory, then the output will also be a directory, named after the name attribute.

Usage

terser_minified(name, config_file, debug, sourcemap, src, terser_bin)

name

(name, mandatory): A unique name for this target.

config_file

(label): A JSON file containing Terser minify() options.

This is the file you would pass to the --config-file argument in terser's CLI. https://github.com/terser-js/terser#minify-options documents the content of the file.

Bazel will make a copy of your config file, treating it as a template.

Run bazel with --subcommands to see the path to the copied file.

If you use the magic strings "bazel_debug" or "bazel_no_debug", these will be replaced with true and false respecting the value of the debug attribute or the --define=DEBUG=1 bazel flag.

For example,

{
    "compress": {
        "arrows": "bazel_no_debug"
    }
}

Will disable the arrows compression setting when debugging.

If config_file isn't supplied, Bazel will use a default config file.

debug

(Boolean): Configure terser to produce more readable output.

Instead of setting this attribute, consider setting the DEBUG variable instead bazel build --define=DEBUG=1 //my/terser:target so that it only affects the current build.

sourcemap

(Boolean): Whether to produce a .js.map output

src

(label, mandatory): File(s) to minify.

Can be a .js file, a rule producing .js files as its default output, or a rule producing a directory of .js files.

Note that you can pass multiple files to terser, which it will bundle together. If you want to do this, you can pass a filegroup here.

terser_bin

(label): An executable target that runs Terser

Changelog

0.38.0 (2019-09-26)

Bug Fixes

• builtin: linker test should run program as an action (#1113) (7f0102e)
• add golden file (9a02ee0)
• add missing async test fixes (12f711a)
• builtin: support for scoped modules in linker (#1199) (94abf68)
• protractor: update rules_webtesting patch to include additional windows fixes (#1140) (f76e97b)
• rollup: npm requires an index.js file (2ababdf)

chore

• cleanup some deprecated APIs (#1160) (cefc2ae), closes #1144

Code Refactoring

• remove http_server and history_server rules (#1158) (01fdeec)

Features

• builtin: detect APF node module format if ANGULAR_PACKAGE file found (#1112) (162e436)
• builtin: expose the new linker to node programs (65d8a36)
• builtin: introduce npm_package_bin (#1139) (2fd80cf)
• builtin: linker should resolve workspace-absolute paths (307a796)
• builtin: npm_package_bin can produce directory output (#1164) (6d8c625)
• examples: demonstrate that a macro assembles a workflow (7231aaa)
• examples: replace examples/webapp with new rollup_bundle (c6cd91c)
• examples: the Angular example now lives in rules_nodejs (9072ddb)
• rollup: ensure that sourcemaps work end-to-end (f340589)
• rollup: new implementation of rollup_bundle in @bazel/rollup package (3873715), closes #532 #724
• rollup: support multiple entry points (f660d39)
• rollup: tests and docs for new rollup_bundle (cfef773)
• terser: support directory inputs (21b5142)
• add angular example (#1124) (c376355)
• terser: support source map files (#1195) (d5bac48)
• typescript: add JSEcmaScriptModuleInfo provider to ts_library outputs (1433eb9)

BREAKING CHANGES

• @bazel/typescript and @bazel/karma no longer have a defs.bzl file. Use index.bzl instead.

The @yarn workspace is no longer created. Use @nodejs//:yarn instead.

• history_server and http_server rules are no longer built-in.

To use them, first install the http-server and/or history-server packages Then load("@npm//http-server:index.bzl", "http_server") (or replace with history-server, noting that the rule has underscore where the package has hyphen)