Module @tapjs/typescript - v1.4.0


A default tap plugin providing typescript support.


This plugin is installed with tap by default. If you had previously removed it, you can tap plugin add @tapjs/typescript to bring it back.

When enabled, this plugin does the following things:

  • adds ts, tsx, cts, mts, and jsx to the file extensions that tap will load.
  • adds ts-node/esm to the loader set.
  • adds the typecheck config flag, which is false by default
  • adds the tsconfig config option, for specifying a project config for your tests to use.

The typecheck config defaults to false, even though type checking your tests is generally a good idea. Unfortunately, it is also often considerably slower, adding as much as 500-750ms to each test suite file, which can be painful if you have a lot of tests. In large project folders, the effect can be even more pronounced.

You can enable type checking with --typecheck on the command line, or by putting typecheck: true in .taprc, or { "tap": { "typecheck": true }} in package.json, or TAP_TYPECHECK=1 in the environment. It is highly recommended to enable it in CI, for example by setting TAP_TYPECHECK=1 in the environment.

The "skipLibCheck": true option in tsconfig will also speed things up a bit, at the expense of some type safety.

Note that even if you pre-compile your tests, they will still be subject to type checking if "allowJs": true is set in your tsconfig.


Set these as command line flags, or in a .taprc or package.json, or via the tap config set <key>=<value> command.

  • typecheck Defaults to false. Applies strict type checking to tests and the files they load, (at the expense of making tests slower).

  • tsconfig Set to the tsconfig.json file to be used when loading TypeScript tests. Defaults to the first of these found, if present: tsconfig.tap.json, tsconfig.test.json, tsconfig.spec.json, tsconfig.json.





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