Implementation of queue

The queue implements the following functions

enqueue() The method of entrance

dequeue() A team approach

top()          Get team leader

size()          Get the number of elements in the queue

clear()        Clear queue

Based on the array

//  Based on the array 
class Queue {
  constructor() {
    this.queue = []
    this.count = 0
  }

  //  The team 
  enQueue(item) {
    this.queue[this.count++] = item
  }

  //  Out of the team 
  deQueue() {
    if (this.isEmpty()) {
      return
    }

    this.count--
    return this.queue.shift()
  }

  isEmpty() {
    return this.count === 0
  }

  //  Get the value of the first element of the team 
  top() {
    return this.queue[0]
  }

  //  Get the number of elements 
  size() {
    return this.count
  }

  //  Clear queue 
  clear() {
    this.queue = []
    this.count = 0
  }
}

Based on the object

class Queue1 {
  constructor() {
    this.queue = {}
    this.count = 0
    this.head = 0 //  The key used to record the head of the team 
  }

  //  The team 
  enQueue(item) {
    this.queue[this.count++] = item
  }

  //  Out of the team 
  deQueue() {
    if (this.isEmpty()) {
      return
    }

    const data = this.queue[this.head]
    delete this.queue[this.head]
    this.head++
    return data
  }

  isEmpty() {
    return this.size() === 0
  }

  //  Get the value of the first element of the team 
  top() {
    return this.queue[0]
  }

  //  Get the number of elements 
  size() {
    return this.count - this.head
  }

  //  Clear queue 
  clear() {
    this.queue = {}
    this.count = 0
    this.head = 0
  }
}

1