百行代码实现js事件监听实现跨页面数据传输
使用场景
类似消息队列的使用场景,支持同页面和跨页面通信,发送消息和接收消息
技术原理
- 跨页面通信:
基于事件监听,通过监听 storage事件监听回调机制,实现跨页面通信,让每个只操作自身页面的操作
- 同页面事件监听:
发送事件时,查找回调函数,触发回调
使用效果
使用示例
// 注册事件
eventListener.addEventListener('showMessage', function (message) {
console.debug("接收到的消息")
})
// 发送事件
eventListener.sendEvent('showMessage', 111)源码
/**
* js 事件监听
*
*
* useage:
* 1. 注册事件监听
* eventListener.addEventListener('xxx-success',function(xxvalue){
* refreshList();
* });
* 发送事件
* 2.eventListener.sendEvent('xxx-success','xxvalue')
*/
/**
* 回调队列
* 结构:{
* eventKey:'xxx',
* callback:[]
* }
*/
let EventListener = function () {
this.callback = [];
this.sendEvent = function (eventKey, eventValue) {
/**
* 同一页面,localStorage.setItem 不触发 storage ,发送时 自动触发
* uuid 保证变更,都能触发 storage事件
*/
let newEventKey = 'evt_' + eventKey;
let uuid = _uuid(8, 16);
let newEventValue = uuid + '_' + (eventValue == undefined ? '' : eventValue);
//手动触发本页面事件
this.triggerCallback(newEventKey, newEventValue);
localStorage.setItem(newEventKey, newEventValue);
}
this.addEventListener = function (eventKey, callback) {
let callbackObject = _findCallbackObject(this, eventKey);
if (callbackObject == undefined) {
callbackObject = {eventKey: eventKey, callback: [callback]};
this.callback.push(callbackObject);
} else {
callbackObject.callback.push(callback);
}
}
/**
* 触发事件对应的回调
* removeItem setItem 都会触发
* removeItem eventValue==null 不触发
*/
this.triggerCallback = function (eventKey, eventValue) {
if (_isEventKey(eventKey) && _isNotNull(eventValue)) {
let originalEventKey = _resolveEventKey(eventKey);
let callbackObject = _findCallbackObject(this, originalEventKey);
if (callbackObject != undefined) {
let callbackQueue = callbackObject.callback;
if (callbackQueue.length > 0) {
eventValue = _resolveEventValue(eventValue);
for (let index in callbackQueue) {
let callback = callbackQueue[index];
try {
callback(eventValue);
} catch (e) {
console.error("执行事件" + callbackObject.eventKey + "的函数失败", e)
}
}
}
//触发后删除
localStorage.removeItem(eventKey);
}
}
}
/**
* 查找到事件key对应的监听对象
*/
function _findCallbackObject(_this, eventKey) {
if (_this.callback.length > 0) {
for (let index in _this.callback) {
let callbackObject = _this.callback[index];
if (callbackObject.eventKey == eventKey) {
return callbackObject;
}
}
}
}
function _resolveEventKey(eventKey) {
return eventKey.split('_')[1];
}
function _isEventKey(eventKey) {
if (eventKey.indexOf('evt_') < 0) {
return false;
}
return true;
}
function _resolveEventValue(eventValue) {
let start = eventValue.indexOf('_') + 1;
let end = eventValue.length;
return eventValue.substring(start, end);
}
function _isNotNull(value) {
if (value == undefined || value == null) {
return false;
}
return true;
}
function _uuid(len, radix) {
let chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('');
let uuid = [], i;
radix = radix || chars.length;
if (len) {
for (i = 0; i < len; i++) uuid[i] = chars[0 | Math.random() * radix];
} else {
let r;
uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-';
uuid[14] = '4';
for (i = 0; i < 36; i++) {
if (!uuid[i]) {
r = 0 | Math.random() * 16;
uuid[i] = chars[(i == 19) ? (r & 0x3) | 0x8 : r];
}
}
}
return uuid.join('');
};
}
let eventListener = new EventListener();
//注册监听,不同页面也可触发监听事件
window.addEventListener('storage', function (event) {
eventListener.triggerCallback(event.key, event.newValue);
})仓库地址: [链接](https://github.com/dushitaoyuan/dev_js_docs/tree/main/event-listener)