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所属分类:Web前端
本文的创作启发来自于Vue中的EventBus(也有人叫中央事件总线),全文系博主原创,转载请标明出处,如有理解不当之处欢迎各位大佬赐教,谢谢!
本文代码秉承发布订阅模式的思想模拟实现了 Vue中的EvnetBus
那么,上代码!
JS版
class Subscription { subscriptionStack = {}; on(eventName, callBack) { if (this.subscriptionStack[eventName]) { this.subscriptionStack[eventName].callBacks.push(callBack); callBack(this.subscriptionStack[eventName].value); } else { console.error("该接口未注册,请先通过emit方法注册接口,再来监听") return; } } emit(eventName, value) { if (this.subscriptionStack[eventName]) { Reflect.set(this.subscriptionStack[eventName], 'value', value); } else { const origin = { value, callBacks: [] } const proxyHandle = { get(origin, key) { return origin[key]; }, set(origin, key, value) { if (key == 'value' && origin.callBacks.length) { origin.callBacks.forEach(callBack => { callBack(value); }) } } } this.subscriptionStack[eventName] = new Proxy(origin, proxyHandle); } } }
Ts版
interface SubscriptionClassInterface { subscriptionStack: object; on(eventName: string, callBack: (val: any) => void): void; emit(eventName: string, value: any): void; } class Subscription implements SubscriptionClassInterface { subscriptionStack: object; on: (eventName: string, callBack: (val: any) => void) => void; emit: (eventName: string, value: any) => void; constructor() { this.subscriptionStack = {}; this.on = (eventName: string, callBack: (val: any) => void) => { if (this.subscriptionStack[eventName]) { this.subscriptionStack[eventName].callBacks.push(callBack); callBack(this.subscriptionStack[eventName].value); } else { console.error("该接口未注册,请先通过emit方法注册接口,再来监听"); return; } }; this.emit = (eventName: string, value: any) => { if (this.subscriptionStack[eventName]) { Reflect.set(this.subscriptionStack[eventName], "value", value); } else { const origin = { value, callBacks: [], }; const proxyHandle = { get(origin, key): any { return origin[key]; }, set(origin, key, value): any { if (key == "value" && origin.callBacks.length) { origin.callBacks.forEach((callBack) => { callBack(value); }); } }, }; this.subscriptionStack[eventName] = new Proxy(origin, proxyHandle); } }; } }
使用方法:
第一步、
# 创建实例 let s = new Subscription();
第二步、
# 发布事件 s.emit(事件名,值) # 举个栗子: s.emit('change',20);
第三步、
# 订阅事件 s.on(事件名,回调函数) > 此处的事件名一定要和emit中的对应上 # 举个栗子: s.on('change',function(val){ //emit中传入的值在Val中接收到 //这里可以写入相应的逻辑代码 //每当再次调用emit这个回调函数会被自动调用,完成响应式 })
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