@bazel/terser
Advanced tools
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
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.
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"],
)
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.
terser_minified(name, args, config_file, debug, sourcemap, src, terser_bin)
name(name, mandatory): A unique name for this target.
args(List of strings): Additional command line arguments to pass to terser.
Terser only parses minify() args from the config file so additional arguments such as --comments may
be passed to the rule using this attribute. See https://github.com/terser/terser#command-line-usage for the
full list of terser CLI options.
Defaults to []
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
--subcommandsto 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 --compilation_mode=dbg 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.
Defaults to @npm_bazel_terser//:terser_config.default.json
debug(Boolean): Configure terser to produce more readable output.
Instead of setting this attribute, consider using debugging compilation mode instead bazel build --compilation_mode=dbg //my/terser:target so that it only affects the current build.
Defaults to False
sourcemap(Boolean): Whether to produce a .js.map output
Defaults to True
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
Defaults to @npm//@bazel/terser/bin:terser
1.0.0 (2019-12-20)
bootstrap attribute & fix $(location) expansions in nodejs_binary templated_args (1860a6a)args to yarn_install & npm_install (#1462) (d245d09)templated_args_file removed from nodejs_binary, nodejs_test & jasmine_node_test. This was a separation of concerns and complicated node.bzl more than necessary while also being rigid in how the params file is formatted. It is more flexible to expose this functionality as another simple rule named params_file.To match standard $(location) and $(locations) expansion, params_file args location expansions are also in the standard short_path form (this differs from the old templated_args behavior which was not Bazel idiomatic) Usage example:
load("@build_bazel_rules_nodejs//:index.bzl", "params_file", "nodejs_binary")
params_file(
name = "params_file",
args = [
"--some_param",
"$(location //path/to/some:file)",
"--some_other_param",
"$(location //path/to/some/other:file)",
],
data = [
"//path/to/some:file",
"//path/to/some/other:file",
],
)
nodejs_binary(
name = "my_binary",
data = [":params_file"],
entry_point = ":my_binary.js",
templated_args = ["$(location :params_file)"],
)
This can be replaced with the --node_options=--require=$(location label) argument such as,
nodejs_test(
name = "bootstrap_test",
templated_args = ["--node_options=--require=$(rlocation $(location :bootstrap.js))"],
entry_point = ":bootstrap.spec.js",
data = ["bootstrap.js"],
)
or
jasmine_node_test(
name = "bootstrap_test",
srcs = ["bootstrap.spec.js"],
templated_args = ["--node_options=--require=$(rlocation $(location :bootstrap.js))"],
data = ["bootstrap.js"],
)
templated_args $(location) and $(locations) are now correctly expanded when there is no space before $(location
such as templated_args = ["--node_options=--require=$(rlocation $(location :bootstrap.js))"].
Path is returned in runfiles manifest path format such as repo/path/to/file. This differs from how $(location)
and $(locations) expansion behaves in expansion the args attribute of a *_binary or *_test which returns
the runfiles short path of the format ./path/to/file for user repo and ../external_repo/path/to/file for external
repositories. We may change this behavior in the future with $(mlocation) and $(mlocations) used to expand
to the runfiles manifest path.
See https://docs.bazel.build/versions/master/be/common-definitions.html#common-attributes-binaries.
args in yarn_install and npm_install can be used to pass arbitrary arguments so we removed the following attributes:npm_package renamed to pkg_npm. This is to match the naming convention for package rules https://docs.bazel.build/versions/master/be/pkg.html.FAQs
Run Terser JS optimizer under Bazel
The npm package @bazel/terser receives a total of 12,818 weekly downloads. As such, @bazel/terser popularity was classified as popular.
We found that @bazel/terser demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 4 open source maintainers collaborating on the project.
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