在不使用Array的情况下在JavaScript中实现类似于Array的行为

const myArray = {
  0: 'value1',
  1: 'value2',
  2: 'value3',
  length: 3,
  push: function(value) {
    this[this.length] = value;
    this.length++;
  },
  pop: function() {
    const value = this[this.length - 1];
    delete this[this.length - 1];
    this.length--;
    return value;
  },
  forEach: function(callback) {
    for (let i = 0; i< this.length; i++) {
      callback(this[i], i, this);
    }
  }
};

myArray.push('value4');
console.log(myArray); // {0: "value1", 1: "value2", 2: "value3", 3: "value4", length: 4}

myArray.pop();
console.log(myArray); // {0: "value1", 1: "value2", 2: "value3", length: 3}

myArray.forEach((value, index) => {
  console.log(`${index}: ${value}`);
});
// 0: value1
// 1: value2
// 2: value3