design-pattern-state.js

class State {
  approve() {
    throw 'Should override this function'
  }
  reject() {
    throw 'Should override this function'
  }
}

class Verifying extends State {
  
  approve(data) {
    console.log('verify succeed', data)
  }
  reject() {
    console.log('verify failed')
  }
  
}

class VerifyFailed extends State {
  
  reject() {
    console.log('verifying')
  }
  
}

class VerifySucceed extends State {

}

class Teacher {

  constructor(state) {

    const states = { Verifying, VerifySucceed, VerifyFailed }
    
    this.currentState = new states[state]()
    this.approve = this.currentState.approve
    this.reject = this.currentState.reject
  }
  
}

const teacherA = new Teacher('Verifying')
teacherA.approve({ name: 'jacky' })