Wechat applet implements a global event bus by itself

Be similar to Vue Global event bus

Have a problem ： Users click to modify avatars in their own small projects , The avatar of the home page needs to be modified synchronously .
Ideas

1. First of all app Bind an attribute to the instance $bus
2. Then create an array to store our events
3. emit Release events , Accept three parameters （ Event name , function , and this Point to ） I practice here by myself because of small projects , Therefore, there is no legal parameter verification and event Whether it is repeated internally
4. on Subscribe to custom events , Because it has been bound this So direct execution
5. off Used to cancel events

export class Bus{
    
  constructor(){
    
    this.event = []
  }
  emit = (eventName,fn,that)=>{
    
      this.event.push({
    
        [eventName]:fn.bind(that)
      })
  }
  on = (eventName,params)=>{
    
    this.event.forEach((v,index)=>{
    
      if(v[eventName]){
    
          v[eventName](params)
          console.log(' The custom event executes ');
      }else{
    
        console.error(" Custom event not found ",eventName)
      }
    })
  }
  off = (eventName)=>{
    
    this.event.forEach((v,index)=>{
    
      if(v[eventName]){
    
        this.event.splice(index,1)
      }
    })
  }
}