WARNING: this is an early release with limited features. Breaking changes are likely. Not recommended for general use.

The TypeScript rules integrate the TypeScript compiler with Bazel.

First, install a current Bazel distribution.

Create a BUILD.bazel file in your project root:

package(default_visibility = ["//visibility:public"])
exports_files(["tsconfig.json"])

# NOTE: this will move to node_modules/BUILD in a later release
filegroup(name = "node_modules", srcs = glob([
    "node_modules/**/*.js",
    "node_modules/**/*.d.ts",
    "node_modules/**/*.json",
]))

Next create a WORKSPACE file in your project root (or edit the existing one) containing:

load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")

git_repository(
    name = "build_bazel_rules_nodejs",
    remote = "https://github.com/bazelbuild/rules_nodejs.git",
    tag = "0.0.2", # check for the latest tag when you install
)

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

node_repositories(package_json = ["//:package.json"])


# Include @bazel/typescript in package.json#devDependencies
local_repository(
    name = "build_bazel_rules_typescript",
    path = "node_modules/@bazel/typescript",
)

We recommend using the Yarn package manager, because it has a built-in command to verify the integrity of your node_modules directory. You can run the version Bazel has already installed:

$ bazel run @yarn//:yarn

Currently, the only available rule is ts_library which invokes the TypeScript compiler on one compilation unit (generally one directory of source files).

Create a BUILD file next to your sources:

package(default_visibility=["//visibility:public"])
load("@build_bazel_rules_typescript//:defs.bzl", "ts_library")

ts_library(
    name = "my_code",
    srcs = glob(["*.ts"]),
    deps = ["//path/to/other:library"],
    tsconfig = "//:tsconfig.json",
)

Then build it:

bazel build //path/to/package:target

The resulting .d.ts file paths will be printed. Additionally, the .js outputs from TypeScript will be written to disk, next to the .d.ts files ¹.

¹ The declarationDir compiler option will be silently overwritten if present.

If you'd like a "watch mode", try https://github.com/bazelbuild/bazel-watcher (note, it's also quite new).

At some point, we plan to release a tool similar to gazelle to generate the BUILD files from your source code.

In the meantime, we suggest associating the .bazel extension with Python in your editor, so that you get useful syntax highlighting.