javascript静态类检测哪个方法调用以前

Question

could you help me! In the emit method how to check they call room method previous or not.
In the two cases below:

// case 1: A.room('aa').emit('a1', 'aaa')
// case 2: A.emit('a2', 'aaa')

this is a class A

class A {
  static room(r) {
    this.r = r
    return this
  }
  static emit(event, data) {
    //todo
    console.log('this.r', this.r, {event, data})
  }
}

Thank for your time!

Answer 1

You need to store flow values like r separately for each call, which is not reasonable aim for static classes because you use same same class again and again, instead of separate instanses. Possible solutions:

1. No longer static :

class A {
    room(r) {
      this.r = r
      return this
    }
    emit(event, data) {
      console.log('this.r', this.r, {event, data})
    }
}
new A().room('aa').emit('a1', 'aaa') // r = 'aa'
new A().emit('a2', 'aaa')            // r = undefined

2. Return instances with own scopes ( A keeps static):

class A {
    static room(r) {
      return new B(r)
    }
    static emit(...args) {
      return new B().emit(...args)
    }
}
class B {
    constructor(r) {
        this.r = r
    }
    emit(event, data) {
        console.log('this.r', this.r, {event, data})
        return this
    }
}
A.room('aa').emit('a1', 'aaa') // r = 'aa'
A.emit('a2', 'aaa')            // r = undefined

3. Delegate logic to non-static class ( A keeps static):

class B {
    room(r) {
      this.r = r
      return this
    }
    emit(event, data) {
      console.log('this.r', this.r, {event, data})
    }
}
class A {
    static room(...args) {
        return new B().room(...args);
    }
    static emit(...args) {
        return new B().emit(...args);
    }
}
A.room('aa').emit('a1', 'aaa') // r = 'aa'
A.emit('a2', 'aaa')            // r = undefined

... and so on.