code: function (key, value) {
          var index = this.indexOfKey(key);
  
          if (index >= 0) {
              this.slot.values[index] = value;
              return;
          }
  
          this.insert(~index, key, value);
      }
docs: Sets the value associated with the specified key.
  @param {Object} key The key whose value to get or set.
  @param {Object} value The value associated with the specified key.