Add TypeScript support

Hi, First, thanks for a great tool! This together with Ink has made writing cli-tools a joy!

But I was wondering if you would be interested in a PR to enable Typescript-files as entrypoints for commands.

I’ve noticed that parcel is used to bundle the scripts and parcel has built in support for TS. And today I can use TS-files if they’re imported deeper in the tree.

I did some fiddling and found a way to at least get started.

I just changed a few lines in lib/read-commands.js:

const readCommands = async (dirPath, buildDirPath) => {
	const paths = fs.readdirSync(dirPath);
	const commands = [];

	const promises = paths.map(async path => {
		// Since `readdir` returns relative paths, we need to transform them to absolute paths
		const fullPath = join(dirPath, path);
		const stats = await stat(fullPath);

		if (stats.isDirectory()) {
			const subCommands = await readCommands(fullPath, join(buildDirPath, path));
			const indexCommand = subCommands.find(isIndexCommand);

			commands.push({
				...indexCommand,
				name: path,
				subCommands: subCommands.filter(command => !isIndexCommand(command))
			});
		}

		if (stats.isFile()) {
			const {description, args} = await parseCommand(fullPath);

			commands.push({
				path: fullPath,
				// -------CHANGES BELOW-------
				buildPath: join(buildDirPath, path.replace('.tsx', '.js')), // This should probably be a more safe regular expression based replace
				name: basename(basename(fullPath, '.js'), '.tsx'),
				// -------CHANGES ABOVE-------
				description,
				args,
				subCommands: []
			});
		}
	});

	await Promise.all(promises);

	return commands;
};

This change deals with the first problem. Now at least both .js- and .tsx-files gets parsed.

But this solutions gives another problem, of course 🤔. If the entrypoint includes interfaces or other typescript features lib/parse-command.js wont be able to parse the file. I would need to dive into the world of Babel in order to see if it’s enough to add @babel/plugin-transform-typescript to make it work, or if a separate typescript based parser is needed.

What do you think? Tell me if you would like me to try it out and see if I could get something working. If you’re not interested, thats fine since I can use Typescript deeper in the tree!

[sindresorhus]

Yeah lib/parse-command.js would need to be modified to parse TS correctly.

Shouldn’t be difficult. Babel supports TypeScript.

Would be even more amazing if it parsed TS types, not just propTypes 😃

That’s a must! propTypes only exist because of lack of static types in JS.

[ChibiBlasphem]

Hello @vadimdemedes Could you publish a new version with the support of typescript ?