利用Object实现简易Map

[hstarorg]

class Map {
  constructor() {
    this.$keyObj = {};
    this.$valueObj = {};
    this.$length = 0;
  }
  set(key, value) {
    const autoKey = `key${Map.idx++}`;   
    this.$keyObj[autoKey] = key;
    this.$valueObj[autoKey] = value;
    // 需要判断是否覆盖来控制 $length
  }
  _getAutoKey(key) {
    const keyItem = Object.entries(this.$keyObj).find(x => x[1] === key);
    return keyItem[0];
  }
  get(key) {
    const autoKey = this._getAutoKey(key);
    if (!autoKey) {
      return undefined;
    }
    return this.$valueObj[autoKey];
  }
}

Map.idx = 1;

// Usage

var map = new Map();
var key = new Object();
map.set(key, 1);
console.log(map.get(key), map.get(key) === 1);