part2_array_list.js

/*
 * array_list
 */

'use strict';

function ArrayList() {
  this.data = [];
  this.length = 0;
}

ArrayList.prototype = {
  constructor: ArrayList,
  append: function (item) {
    this.data[this.length] = item;
    this.length ++;
  },
  remove2: function (index) {
    this.check(index);
    var item = this.data[index];
    this.data.splice(index,1);
    this.length --;
    return item;
  },
  remove: function (index) {
    this.check(index);
    var item = this.data[index];
    for (var i = index; i < this.data.length; i += 1) {
      this.data[i] = this.data[i+1];
    }
    // TODO js删除数组元素只能用splice方法，不存在的元素是undefined
    // this.data.splice(this.length,1); // 这一句话没作用？？
    this.length --;
    return item;
  },
  size: function () {
    return this.length;
  },
  insert2: function (index, item) {
    this.check(index);
    this.data.splice(index, 0, item);
    this.length ++;
  },
  insert: function (index, item) {
    this.check(item);
    for (var i = this.length; i >= index; i -= 1) {
      this.data[i] = this.data[i-1];
    }
    this.data[index] = item;
    this.length ++;
  },
  check: function (index) {
    if(typeof index !== 'number') {
      throw 'index should be number';
    }
    if(index < 0 || index > this.length) {
      throw 'index should large than 0 and less than this.size()';
    }
  }
};

module.exports = ArrayList;