如何为微信小程序添加event事件监听功能？

1. 在utils下新建一个event.js的类文件

class Event {
    on(event, fn) {
        if (typeof fn != "function") {
            console.error('fn must be a function')
            return
        }

        this._stores = this._stores || {}

        ; (this._stores[event] = this._stores[event] || []).push(fn)
    }
    emit(event) {
        this._stores = this._stores || {}
        var store = this._stores[event], args
        if (store) {
            store = store.slice(0)
            args = [].slice.call(arguments, 1)
            for (var i = 0, len = store.length; i < len; i++) {
                store[i].apply(null, args)
            }
        }
    }
    off(event, fn) {
        this._stores = this._stores || {}
        // all
        if (!arguments.length) {
            this._stores = {}
            return
        }
        // specific event
        var store = this._stores[event]
        if (!store) return
        // remove all handlers
        if (arguments.length === 1) {
            delete this._stores[event]
            return
        }
        // remove specific handler
        var cb
        for (var i = 0, len = store.length; i < len; i++) {
            cb = store[i]
            if (cb === fn || cb.fn === fn) {
                store.splice(i, 1)
                break
            }
        }
        return
    }
}
module.exports = {
    Event
}

1. 导入到app.js中

import {Event} from '/utils/event.js'
wx.event = new Event();

1. 事件钩子挂载

var addfun = function(x,y){
    return x+y;
}
wx.event.on('change',addfun)

1. 事件监听

var sum = wx.event.emit('change',x,y);

1. 事件取消

wx.event.off('change',addfun)

代码出处：qingdian