Class ArrayList

specs/arrays/arraylist.solution.test.js:20–53

*/

class ArrayList {
  constructor() {
    this.length = 0;
    this.data = {};
  }
  push(value) {
    this.data[this.length] = value;
    this.length++;
  }
  pop() {
    const ans = this.data[this.length - 1];
    delete this.data[this.length - 1];
    this.length--;
    return ans;
  }
  get(index) {
    return this.data[index];
  }
  delete(index) {
    const ans = this.data[index];
    this._collapseTo(index);
    return ans;
  }
  _collapseTo(index) {
    for (let i = index; i < this.length; i++) {
      this.data[i] = this.data[i + 1];
    }
    delete this.data[this.length - 1];
    this.length--;
  }
  serialize() {
    return this.data;
  }
}

// unit tests
// do not modify the below code