watch always watches .js

[tomitrescak]

Prerequisites

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• Checked next-gen ES issues and syntax problems by using the same environment and/or transpiler configuration without Mocha to ensure it isn't just a feature that actually isn't supported in the environment in question or a bug in your code.
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Description

This is not an issue but feature request.

Watch mode always watches for ".js" files even when I specify --watch-extensions to be "ts,tsx". Is it possible to change the behaviour to strictly watch only the specified extensions?

[tomitrescak]

Why is this a problem? Well, even whan I specify to be my test and folder to be in 'src/' mocha watches files outside of these directories. For example in ".fusebox' where my bundler stores cached files.

[outsideris]

Did you see #2554 or #1780 .
I don't know all history of mocha, but it seems mocha.js want to drop the watch feature rather than enhance it.

[boneskull]

I would love to drop this feature, but I don't think that's going to happen.

Too many people use it.

It should be fixed. It shouldn't necessarily receive new features, but it should work as expected.

I'd consider this to be a bug.

UPDATE: This isn't a bug, because it works as intended, but I agree that the intention should be different. That makes it a breaking change, FWIW.

[plroebuck]

@tomitrescak, not a TypeScript guy myself... Are watched files your only issue? What about the default files to test? Here are the relevant portions of code related to this question.

mocha/bin/_mocha

Lines 450 to 462 in c580294

	const extensions = ['js'];
	program.compilers.forEach(c => {
	const idx = c.indexOf(':');
	const ext = c.slice(0, idx);
	let mod = c.slice(idx + 1);
	if (mod[0] === '.') {
	mod = join(process.cwd(), mod);
	}
	require(mod);
	extensions.push(ext);
	program.watchExtensions.push(ext);
	});

mocha/bin/_mocha

Lines 478 to 515 in c580294

	// default files to test/*.{js,coffee}
	if (!args.length) {
	args.push('test');
	}
	args.forEach(arg => {
	let newFiles;
	try {
	newFiles = utils.lookupFiles(arg, extensions, program.recursive);
	} catch (err) {
	if (err.message.indexOf('cannot resolve path') === 0) {
	console.error(`Warning: Could not find any test files matching pattern: ${arg}`);
	return;
	}
	throw err;
	}
	files = files.concat(newFiles);
	});
	if (!files.length) {
	console.error('No test files found');
	process.exit(1);
	}
	// resolve
	let fileArgs = program.file.map(path => resolve(path));
	files = files.map(path => resolve(path));
	if (program.sort) {
	files.sort();
	}
	// add files given through --file to be ran first
	files = fileArgs.concat(files);

Note the variable program.watchExtensions deals with which files to watch. The variable extensions (for "native/transpiled" code) is used to determine which files are selected for testing.

[tomitrescak]

Nevermind this, I solved it with using a node-watcher.