README.md

Bazel JavaScript Examples

Examples demonstrate building JavaScript with Bazel.

Bazel	JavaScript	NodeJs	Yarn

Installing

Following the official guide to install bazel.

Runnging the examples

Run bazel query ... for available targets.

For example, running the nodejs binary example:

$ bazel run //src/node:app

If everything goes well, it will print hello, {name}.

What's included in this example

1. A basic setup for building JavaScript using bazel

bazel.rc

bazel.rc contains the most common setup for bazel.

• build --symlink_prefix=/ avoids creating symlinks like bazel-out in the project root. The output's annoy and cause performance issue with the editor.
• query --output=label_kind more usful when prints the query result with name and kind.

WORKSPACE

WORKSPACE contains minimal setup for building the JavaScript code.

• load rules and setup for nodejs

git_repository(
    name = "build_bazel_rules_nodejs",
    remote = "https://github.com/bazelbuild/rules_nodejs.git",
    tag = "0.15.0", # check for the latest tag when you install
)

load("@build_bazel_rules_nodejs//:package.bzl", "rules_nodejs_dependencies")
rules_nodejs_dependencies()

• install nodejs, npm and yarn for the project

load("@build_bazel_rules_nodejs//:defs.bzl", "node_repositories")

# NOTE: this rule installs nodejs, npm, and yarn, but does NOT install
# your npm dependencies into your node_modules folder.
# You must still run the package manager to do this.
node_repositories(package_json = ["//:package.json"])

• Using Bazel-managed dependencies

load("@build_bazel_rules_nodejs//:defs.bzl", "yarn_install")

yarn_install(
    name = "npm",
    package_json = "//:package.json",
    yarn_lock = "//:yarn.lock",
)

2. Buildifier

Using Buidifier form bazelbuild/buildtools to generate and format bazel files.

The setup code locates in the root BUILD.bazel file and format code with the following command:

$ bazel run //:buildifier

3. Loading and consume packages from npm

When runing bazel the first time, it will automatically install dependencies. Alternatively you can manually install by running:

$ bazel run @nodejs//:yarn

Access the npm packages within BUILD.bazel With the fine-grained npm package dependencies setup in WORKSPACE.

load("@build_bazel_rules_nodejs//:defs.bzl", "nodejs_binary")

nodejs_binary(
    name = "app",
    install_source_map_support = False,
    data = [
        "index.js",
        "lib.js",
        "@npm//lodash",
    ],
    entry_point = "bazel_js_example/src/node/index.js",
)

4. Running node binary from npm packages

Run the rollup binary example install from npm.

all params after -- will path through to the binary

$ bazel run //src/rollup:rollup -- -v

nodejs_binary(
    name="rollup",
    install_source_map_support = False,
    entry_point = "rollup/bin/rollup",
    data = [
        "@npm//rollup",
    ],
)

5. Bundle js with rollup

Bundle js with rollup_bundle rules.

$ bazel build //src/rollup_bundle:bundle

nodejs_binary(
    name="rollup",
    install_source_map_support = False,
    entry_point = "rollup/bin/rollup",
    data = [
        "@npm//rollup",
    ],
)

6. Stamping

Currently not avaialbe. Refer bazelbuild/bazel#1054 for more updates.

7. Publishing to npm

Run bazel build //src/npm_package:sample_package to generate publishable files.

load("@build_bazel_rules_nodejs//:defs.bzl", "npm_package")
npm_package(
    name = "sample_package",
    srcs = [
        "index.js",
        "lib.js",
        "package.json",
    ],
    replacements = {"//internal/": "//"},
    deps = [
        "@npm//lodash",
    ],
)