观察者模式之ES6实现（一）

一、参考链接

https://github.com/JacksonTian/eventproxy/tree/master/lib

二、代码实现

// eventProxy.js
'use strict';
const eventProxy = {
    onObj: {},
    oneObj: {},
    on: function(key, fn) {
        if(this.onObj[key] === undefined) {
            this.onObj[key] = [];
        }
        this.onObj[key].push(fn);
    },
    one: function(key, fn) {
        if(this.oneObj[key] === undefined) {
            this.oneObj[key] = [];
        }
        this.oneObj[key].push(fn);
    },
    off: function(key) {
        this.onObj[key] = [];
        this.oneObj[key] = [];
    },
    trigger: function() {
        let key, args;
        if(arguments.length == 0) {
            return false;
        }
        key = arguments[0];
        args = [].concat(Array.prototype.slice.call(arguments, 1));

        if(this.onObj[key] !== undefined
          && this.onObj[key].length > 0) {
            for(let i in this.onObj[key]) {
                this.onObj[key][i].apply(null, args);
            }
        }
        if(this.oneObj[key] !== undefined
          && this.oneObj[key].length > 0) {
            for(let i in this.oneObj[key]) {
                this.oneObj[key][i].apply(null, args);
                this.oneObj[key][i] = undefined;
            }
            this.oneObj[key] = [];
        }
    }
};

export default eventProxy;