alchemymvc/lib/scripts/setup_devwatch.js

MVC framework for Node.js

'use strict';

if (process.argv.indexOf('--disable-devwatch') > -1) {
	return;
}

if (!alchemy.settings.debugging.kill_on_file_change) {
	return;
}

const chokidar = alchemy.use('chokidar');

if (!chokidar) {
	log.warn('Can not watch files because Chokidar is not installed');
	return;
}

let allowedPattern,
    extensions,
    prevcount,
    watchlog,
    watcher,
    allowed,
    ignored,
    count,
    cwd,
    fs;

fs = alchemy.use('fs');

prevcount = 0;
count = 0;

ignored = /^app\/public\/views|^temp/;
extensions = ['js', 'json'];
cwd = process.cwd();

// Get the extensions allowed to kill the server
if (Array.isArray(alchemy.settings.debugging.kill_extensions)) {
	extensions = alchemy.settings.debugging.kill_extensions;
}

allowedPattern = '';

// Go over every extensionin the array
extensions.forEach(function eachExtension(extension) {

	if (allowedPattern) {
		allowedPattern += '|';
	}

	allowedPattern += '\\.' + extension + '$';
});

// Create the regex
allowed = new RegExp(allowedPattern);

watchlog = Function.throttle(function watchlog() {

	if (prevcount == count) {
		return;
	}

	log.warn(count, 'files are being monitored for changes');
	prevcount = count;
}, 1500, false, true);

// Use a map to log path results, because chokidar calls the `ignored`
// option multiple times for each file
let seen_map = new Map();

// Start watching all the files, starting with the current working directory
watcher = chokidar.watch(cwd, {ignored: function ignoreThisPath(_path) {

	let cached = seen_map.get(_path);

	if (cached != null) {
		return cached;
	}

	let isAllowed,
		path = _path,
		stat = arguments[1],
		file;

	// Ignore git folders
	if (~path.indexOf('.git')) {
		seen_map.set(_path, true);
		return true;
	}

	// Ignore non-stylesheet files in asset or public folders
	if (~path.indexOf('/assets/') || ~path.indexOf('/public/')) {
		// DO watch less files, for the stylesheet reload!
		if (path.indexOf('.') > -1 && !path.endsWith('.less') && !path.endsWith('.css') && !path.endsWith('.scss')) {
			seen_map.set(_path, true);
			return true;
		} else {
			isAllowed = true;
		}
	}

	// Skip some big module folders by default
	if (path.endsWith('/less') || path.endsWith('/caniuse-lite') || path.endsWith('/bcrypt') || path.endsWith('/sass') || path.endsWith('/mmmagic') || path.endsWith('/node-gyp') || path.endsWith('/lodash')) {
		seen_map.set(_path, true);
		return true;
	}

	watchlog();

	if (count > 4999) {
		if (count == 5000) {
			count++
			log.warn('Already watching 5000 files, not watching any more');
		}

		seen_map.set(_path, true);
		return true;
	}

	path = path.replace(cwd+'/', '');
	file = path.split('/');
	file = file[file.length-1];

	if (file == 'package.json' || file == 'package-lock.json' || file.startsWith('scratch')) {
		seen_map.set(_path, true);
		return true;
	}

	if (path.count('/coverage/') || path.count('/.') || path.count('/test/') || path.count('/benchmark/') || path.count('/deoptigate/')) {
		seen_map.set(_path, true);
		return true;
	}

	if (isAllowed == null) {
		// Only allow the specified extensions
		isAllowed = allowed.exec(file);
	}

	// If it's already false, return it
	if (!isAllowed) {
		// Only disallow if it's not a directory
		try {

			// The stat supplied by chokidar (if it is suppliad at all)
			// does not follow symlinks, so *sigh* get it again
			stat = fs.statSync(path);

			if (!stat.isDirectory()) {
				seen_map.set(_path, true);
				return true;
			}
		} catch (err) {
			seen_map.set(_path, true);
			// Ignore files that have been removed
			return true;
		}
	}

	// See if it's still allowed based on patterns to ignore
	isAllowed = !ignored.exec(path);

	if (isAllowed && path.count('/plugins/') == 1 && path.count('node_modules')) {
		isAllowed = false;
	}

	if (isAllowed && path.count('node_modules')) {
		if (path.count('/codecov/') || path.count('/mocha/') || path.count('/nyc/')) {
			isAllowed = false;
		}
	}

	// If it's still allowed, make sure it isn't 2 or more node_modules deep
	if (isAllowed && path.count('node_modules') > 1) {

		if (path.count('node_modules') == 2 && path.endsWith('node_modules')) {
			isAllowed = true;
		} else if (path.count('protoblast') || path.count('hawkejs') || path.count('janeway')) {
			if (path.count('node_modules') > 2) {
				isAllowed = false;
			}
		} else {
			isAllowed = false;
		}
	}

	// If it's still allowed, increase the watch count
	if (isAllowed) {
		count++;
	}

	seen_map.set(_path, !isAllowed);

	// Return if it should be ignored or not
	return !isAllowed;

}, persistent: true});

// Kill the server when any of the files change
watcher.on('change', function onFileChange(path, stats) {

	// Skip hawkejs client file
	if (path.indexOf('hawkejs-client-side.js') > -1) {
		return false;
	}

	// Skip protoblast client files
	if (path.indexOf('protoblast/client-file') > -1) {
		return false;
	}

	// Also skip files in the temp directory
	if (path.indexOf('temp/') === 0) {
		return false;
	}

	// Skip assets or public files
	if (path.indexOf('/assets/') > -1 || path.indexOf('/public/') > -1) {

		if (path.endsWith('.css') || path.endsWith('.scss') || path.endsWith('.less')) {
			broadcastReload(path);
		}

		return false;
	}

	// Only allow defined extensions
	if (!allowed.exec(path)) {
		return false;
	}

	// Kill the process, run together with something like "forever" to restart
	die('Killing server because', JSON.stringify(path.replace(cwd + '/', '')), 'has been modified');
});

let broadcastReload = Function.throttle(function broadcastReload(path) {
	alchemy.broadcast('css_reload', path);
}, 10, false, true);