Adds TypeScript support to AVA.

This is designed to work for projects that precompile TypeScript. It allows AVA to load the compiled JavaScript, while configuring AVA to treat the TypeScript files as test files.

In other words, say you have a test file at src/test.ts. You've configured TypeScript to output to build/. Using @ava/typescript you can run the test using npx ava src/test.ts and ava will pretend that the test came from the typescript file.

Add this package to your project:

npm install --save-dev @ava/typescript

Then, enable TypeScript support either in package.json or ava.config.*:

package.json:

{
	"ava": {
		"typescript": {
			"rewritePaths": {
				"src/": "build/"
			},
			"compile": false
		}
	}
}

As configured above, the "rewritePaths" option means that AVA's internal representation of the paths will be changed from "src/" to "build/" (note that the key and value must end in a "/"). Paths are relative to your project directory.

You can enable compilation via the compile property. If false, AVA will assume you have already compiled your project. If set to 'tsc', AVA will run the TypeScript compiler before running your tests. This can be inefficient when using AVA in watch mode.

Output files are expected to have the .js extension.

AVA searches your entire project for *.js, *.cjs, *.mjs, *.ts, *.cts and *.mts files (or other extensions you've configured). It will ignore such files found in the rewritePaths targets (e.g. build/). If you use more specific paths, for instance build/main/, you may need to change AVA's files configuration to ignore other directories.

If your package.json has configured "type": "module", or you've configured AVA to treat the js extension as module, then @ava/typescript will import the output file as an ES module. Note that this is based on the output file, not the ts extension.

You can configure AVA to recognize additional file extensions. To add (partial†) JSX support:

package.json:

{
	"ava": {
		"typescript": {
			"extensions": [
				"ts",
				"tsx"
			],
			"rewritePaths": {
				"src/": "build/"
			}
		}
	}
}

If you use the allowJs TypeScript option you'll have to specify the js, cjs and mjs extensions for them to be rewritten.

See also AVA's extensions option.

† Note that the preserve mode for JSX is not (yet) supported.