rules_tsickle

What?

rules_tsickle provides a closure_ts_compile rule that transforms .ts files into closure-annotated .js files. It contains a vendored copy of https://github.com/angular/tsickle (which was archived in May 2025).

Why?

The primary reason rules_tsickle was created was to perform .ts to .js translation of https://github.com/google/safevalues for https://github.com/google/closure-templates/tree/master/javascript. Several of the soyutils files in that repo have closure dependencies like:

goog.require('google3.third_party.javascript.safevalues.index');

No open-source copy of the translated .js files could be located, so rules_tsickle was created to perform that translation.

How?

To use rules_tsickle in your own bazel workspace (lookup most recent version):

bazel_dep("rules_tsickle", version = "0.0.0")

Then, in a package containing .ts and/or .d.ts files:

load("//rules:defs.bzl", "closure_ts_compile")

closure_ts_compile(
    name = "index",
    srcs = ["index.ts"],
)

bazel build :index will:

• download npm deps and prepare the js_binary tsickle runner (//tools/tsicklecompiler).
• run the tool, which roughly works as follows:
  • prepare an internal/minimal tsconfig.json configuration.
  • runs tsc over the inputs to generate a ts.Program
  • runs tsickle over the ts.Program to AST-rewrite/transform it.
  • emits the transformed .js files.
• output files:
  • each {basename}.ts will produce an equivalent {basename}.js file
  • if any .d.ts files are present, a single {name}-externs.js file will be produced.

closure_ts_compile can take deps on other closure_ts_compile rules. The source .ts files will be made available to tsc. Only direct .ts files in the primary rule will emitted.

Versioning

The rules_tsickle initial version is 1.0.0 not because of a long history of development, but because it is anticipated this repo will not see a large amount of future development.