weakset/index.js

Leak-free WeakSet polyfill.

/**
 * @module WeakSet
 */
var counter = Date.now() % 1e9;


/**
 * @constructor
 */
function WeakSet (data) {
  this.name = '__st' + (Math.random() * 1e9 >>> 0) + (counter++ + '__');
  data && data.forEach && data.forEach(this.add, this);
};


var proto = WeakSet.prototype;

proto['add'] = function(val) {
  var name = this.name;
  if (!val[name]) Object.defineProperty(val, name, {value: true, writable: true});
  return this;
};
proto['delete'] = function(val) {
  if (!val[this.name]) return false;
  val[this.name] = undefined;
  return true;
};
proto['has'] = function(val) {
  return !!val[this.name];
};

module.exports = WeakSet;