gulp-tasks-manager/lib/tasks.js

Gulp tasks manager

var path = require('path');

module.exports = tasks;

var taskCache = Object.create(null);

/**
 * @param  {Object} gulp    gulp
 * @param  {Object} plugins gulp-load-plugins or self defined object
 * @param  {Object} opts    options
 * @return {Function} function to load subtasks
 */
function tasks(gulp, plugins, opts) {
	opts = opts || {};
	opts.rootDir = opts.rootDir || './';
	opts.taskDir = opts.taskDir || './';

	return function task(name, filename) {
		if (taskCache[name]) {
			throw new Error('Duplicate namespace: ' + name);
		}

		filename = filename || name;

		var taskPath = path.join(opts.taskDir, filename),
			executor = require(path.resolve(taskPath));

		if (typeof executor !== 'function') {
			throw new Error('module.exports of ' + taskPath + ' must be a function');
		}

		var subTasks = [],
			ns = function(taskName) {
				if (typeof taskName === 'string') {
					taskName = name + ':' + taskName;
					if (subTasks.indexOf(taskName) > -1) {
						throw new Error('Duplicate task name: ' + taskName);
					}
					subTasks.push(taskName);
					return taskName;
				}

				if (Array.isArray(taskName)) {
					return taskName.map(function(item) {
						return name + ':' + item;
					});
				}

				throw new Error('The function ns(taskName) must take a string ' +
					'or an array of strings as its only parameter');
			};

		ns.name = name;
		ns.context = function(dir) {
			var cxt = path.join(opts.rootDir, dir);
			return function(rel) {
				return path.join(cxt, rel);
			};
		};

		executor(gulp, plugins, ns);
		gulp.task(name, subTasks);
		taskCache[name] = subTasks;
	};
}

/**
 * List main tasks managed by this tool.
 * 
 * @return {Array} main tasks, i.e. all namespaces
 */
tasks.list = function() {
	return Object.keys(taskCache);
};

/**
 * List all tasks managed by this tool.
 * 
 * @return {Object} all tasks
 */
tasks.listAll = function() {
	return taskCache;
};