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Version: 2.1.x

Bazel rules for TypeScript

This is the canonical ruleset for using Bazel with TypeScript, based on

Many companies are successfully building with rules_ts. If you're getting value from the project, please let us know! Just comment on our Adoption Discussion.

This is a high-performance alternative to the @bazel/typescript npm package from rules_nodejs. The ts_project rule here is identical to the one in rules_nodejs, making it easy to migrate. Since rules_js always runs tools from the bazel-out tree, rules_ts naturally fixes most usability bugs with rules_nodejs:

  • Freely mix generated *.ts and tsconfig.json files in the bazel-out tree with source files
  • Fixes the need for any rootDirs settings in tsconfig.json as reported in
  • "worker mode" for ts_project now shares workers across all targets, rather than requiring one worker pool per target

rules_ts is just a part of what Aspect provides:

Known issues:


Follow instructions from the release you wish to use:


There are a number of examples in the examples/ folder and larger examples in the bazel-examples repository using rules_ts such as jest, react, angular.

If you'd like an example added, you can fund a Feature Request.


See the API documentation in the docs/ folder.

From a BUILD file

The most common use is with the ts_project macro which invokes a transpiler you configure to transform source files like .ts files into outputs such as .js and, and the tsc CLI to type-check the program and produce .d.ts files.

In a macro

Many organizations set default values, so it's common to write a macro to wrap ts_project, then ensure that your developers load your macro rather than loading from @aspect_rules_ts directly.

BUILD file generation

Aspect provides a TypeScript BUILD file generator as part of the Aspect CLI. Run aspect configure to create or update BUILD.bazel files as you edit TypeScript sources. See

Advanced: custom rules

If you know how to write Bazel rules, you might find that ts_project doesn't do what you want.

One way to customize it is to peel off one layer of indirection, by calling the ts_project_rule directly. This bypasses our default setting logic, and also the validation program which checks that ts_project attributes are well-formed.

You can also write a custom rule from scratch. We expose helper functions from /ts/private in this repo. Be aware that these are not a public API, so you may have to account for breaking changes which aren't subject to our usual semver policy.