封装好的observer.js，用于非父子组件传值，直接调用$on和$emit方法

const eventList = {} const $on = (eventName,callback)=>{ if(!eventList[eventName]){ eventList[eventName] = []; } eventList[eventName].push(callback) } const $emit = (eventName,params)=>{ if(eventList[eventName]){ let arr = eventList[eventName]; arr.map((cb)=>{ cb(params); }) } } const $off = (eventName,callback)=>{ if(eventList[eventName]){ if(callback){ let index = eventList[eventName].indexOf(callback); eventList[eventName].splice(index,1); }else{ eventList[eventName].length = 0; } } } export default { $on, $emit, $off }