refactor: events module

.eslintrc.json

@@ -4,7 +4,7 @@
     "mocha": true
   },
   "parserOptions": {
-    "ecmaVersion": 6
+    "ecmaVersion": 11
   },
   "extends": "google",
   "rules": {

lib/events.js

@@ -1,7 +1,6 @@
 'use strict';
 
 // Modules.
-const _ = require('lodash');
 const EventEmitter = require('events').EventEmitter;
 const Log = require('./logger');
 const Promise = require('./promise');
@@ -15,6 +14,7 @@ class AsyncEvents extends EventEmitter {
     super();
     // Set things
     this.log = log;
+    /** @type {{ name: string, priority: number; fn: Function }[]} */
     this._listeners = [];
   };
 
@@ -25,8 +25,8 @@ class AsyncEvents extends EventEmitter {
    *
    * @since 3.0.0
    * @alias lando.events.on
-   * @param {String} name The name of the event
-   * @param {Integer} [priority=5] The priority the event should run in.
+   * @param {string} name The name of the event
+   * @param {number} [priority=5] The priority the event should run in.
    * @param {Function} fn The function to call. Should get the args specified in the corresponding `emit` declaration.
    * @return {Promise} A Promise
    * @example
@@ -43,8 +43,7 @@ class AsyncEvents extends EventEmitter {
    */
   on(name, priority, fn) {
     // Handle no priority
-    // @todo: is there a way to get this working nicely via es6?
-    if (_.isUndefined(fn) && _.isFunction(priority)) {
+    if (typeof fn === 'undefined' && typeof priority === 'function') {
       fn = priority;
       priority = 5;
     }
@@ -63,8 +62,8 @@ class AsyncEvents extends EventEmitter {
    *
    * @since 3.0.0
    * @alias lando.events.emit
-   * @param {String} name The name of the event
-   * @param {...Any} [args] Options args to pass.
+   * @param {string} name The name of the event
+   * @param {...any} args Options args to pass.
    * @return {Promise} A Promise
    * @example
    * // Emits a global event with a config arg
@@ -73,46 +72,37 @@ class AsyncEvents extends EventEmitter {
    * // Emits an app event with a config arg
    * return app.events.emit('sector001', config);
    */
-  emit(...args) {
-    /*
+  emit(name, ...args) {
+    /**
      * Helper function that will always return a promise even if function is
      * synchronous and doesn't return a promise.
-     * @todo: this is very old kbox code, can we update it a bit?
+     *
+     * @param {Function} fn
+     * @param {...any} args
+     * @return {Promise}
      */
-    const handle = (...args) => {
-      const fn = args.shift();
+    const handle = (fn, ...args) => {
       const result = fn.apply(this, args);
       return Promise.resolve(result);
     };
     // Save for later
     const self = this;
-    // Grab name of event from first argument.
-    const name = args.shift();
 
-    // Grab priority sorted listeners for this event
-    const evnts = _(this._listeners)
-      // Filter by name
+    const fns = this._listeners
       .filter(listener => listener.name === name)
-      // Sort by priority
-      .sortBy('priority')
-      // Return value
-      .value();
-
-    // Map to array of func
-    const fns = _.map(evnts, evnt => evnt.fn);
+      .sort((a, b) => a.priority - b.priority)
+      .map(evnt => evnt.fn);
 
     // Log non engine events so we can keep things quiet
-    if (!_.includes(name, '-engine-')) {
+    if (!name.includes('-engine-')) {
       this.log.debug('emitting event %s', name);
       this.log.silly('event %s has %s listeners', name, fns.length);
     }
 
     // Make listener functions to a promise in series.
     return Promise.each(fns, fn => {
       // Clone function arguments.
-      const fnArgs = args.slice();
-      // Add listener function to front of arguments.
-      fnArgs.unshift(fn);
+      const fnArgs = [fn, ...args];
       // Apply function that calls the listener function and returns a promise.
       return handle.apply(self, fnArgs);
     })