/*! * use <https://github.com/jonschlinkert/use> * * Copyright (c) 2015, 2017, Jon Schlinkert. * Released under the MIT License. */ 'use strict'; var utils = require('./utils'); module.exports = function base(app, opts) { if (!utils.isObject(app) && typeof app !== 'function') { throw new TypeError('use: expect `app` be an object or function'); } if (!utils.isObject(opts)) { opts = {}; } var prop = utils.isString(opts.prop) ? opts.prop : 'fns'; if (!Array.isArray(app[prop])) { utils.define(app, prop, []); } /** * Define a plugin function to be passed to use. The only * parameter exposed to the plugin is `app`, the object or function. * passed to `use(app)`. `app` is also exposed as `this` in plugins. * * Additionally, **if a plugin returns a function, the function will * be pushed onto the `fns` array**, allowing the plugin to be * called at a later point by the `run` method. * * ```js * var use = require('use'); * * // define a plugin * function foo(app) { * // do stuff * } * * var app = function(){}; * use(app); * * // register plugins * app.use(foo); * app.use(bar); * app.use(baz); * ``` * @name .use * @param {Function} `fn` plugin function to call * @api public */ utils.define(app, 'use', use); /** * Run all plugins on `fns`. Any plugin that returns a function * when called by `use` is pushed onto the `fns` array. * * ```js * var config = {}; * app.run(config); * ``` * @name .run * @param {Object} `value` Object to be modified by plugins. * @return {Object} Returns the object passed to `run` * @api public */ utils.define(app, 'run', function(val) { if (!utils.isObject(val)) return; decorate(val); var self = this || app; var fns = self[prop]; var len = fns.length; var idx = -1; while (++idx < len) { val.use(fns[idx]); } return val; }); /** * Call plugin `fn`. If a function is returned push it into the * `fns` array to be called by the `run` method. */ function use(fn, options) { if (typeof fn !== 'function') { throw new TypeError('.use expects `fn` be a function'); } var self = this || app; if (typeof opts.fn === 'function') { opts.fn.call(self, self, options); } var plugin = fn.call(self, self); if (typeof plugin === 'function') { var fns = self[prop]; fns.push(plugin); } return self; } /** * Ensure the `.use` method exists on `val` */ function decorate(val) { if (!val.use || !val.run) { base(val); } } return app; };