Bazel	NodeJs

rules_node

Put rules_node in your WORKSPACE and load the main repository dependencies. This will download the nodejs toolchain including node (6.6.x) and npm.

git_repository(
    name = "org_pubref_rules_node",
    tag = "v0.2.0",
    remote = "https://github.com/pubref/rules_node.git",
)

load("@org_pubref_rules_node//node:rules.bzl", "node_repositories")

node_repositories()

Rules

Rule	Description
node_repositories	Install node toolchain.
npm_library	Declare an external npm dependency.
node_library	Define a local npm module.
node_binary	Build or execute a nodejs script.

Example

load("@org_pubref_rules_node//node:rules.bzl", "node_binary", "npm_library")

npm_library(
    name = "glob",
)

npm_library(
    name = "react-stack",
    deps = {
        "react": "15.3.2",
        "react-dom": "15.3.2",
    },
)

node_binary(
    name = "foo",
    main_script = "foo.js",
    npm_deps = ["glob", "react-stack"],
)

node_repositories

WORKSPACE rule. No current options.

npm_library

Declares a set of npm dependencies. Functionally equivalent to npm install ....

Takes two forms:

1. Single import: uses the name of the rule (see glob above).

2. Multiple import: uses a string_dict declaring the name@version dependency. (see react-stack above).

node_library

This rule accepts a list of srcs (*.js) and other configuration attributes. When depended upon, it generates a package.json file describing the module and the npm install's it in a local node_modules folder. The name of the module is the package label, substituting / (slash) with - (dash). For example:

load("//node:rules.bzl", "node_library")

node_library(
    name = "baz",
    main_script = "index.js",
    srcs = [
        "qux.js"
    ],
    npm_deps = ["glob"],
    use_prefix = False,
)

Is installed as:

INFO: From NpmInstallLocal examples/baz/lib/node_modules/examples-baz/package.json:
/private/var/tmp/_bazel_user/178d7438552046b1be3cba61fe7b75a8/execroot/rules_node/bazel-out/local-fastbuild/bin/examples/baz/lib
`-- examples-baz@0.0.0
  `-- glob@7.1.0
    +-- fs.realpath@1.0.0
    +-- inflight@1.0.5
    | `-- wrappy@1.0.2
    +-- inherits@2.0.3
    +-- minimatch@3.0.3
    | `-- brace-expansion@1.1.6
    |   +-- balanced-match@0.4.2
    |   `-- concat-map@0.0.1
    +-- once@1.4.0
    `-- path-is-absolute@1.0.0

And can be require()'d in another module as follows:

var baz = require("examples-baz");
console.log('Hello, ' + baz());

This packaging/install cycle occurs on demand and is a nicer way to develop nodejs applications with clear dependency requirements. Bazel makes this very clean and convenient.

node_binary

Creates an executable script that will run the file named in the main_script attribute. Paths to dependent node_library and npm_library rules (each one having a node_modules subdirectory) are used to construct a NODE_PATH environment variable that the node executable will use to fulfill require dependencies.

---

WARNING: these rules are not hermetic (or by that measure, secure)! It trusts that the npm install command does what is it supposed to do, and there is no current support for validating that a particular npm package(s) matches a sha256 (this is the the norm for npm, but it's sub-standard for bazel).