基于JavaScript(Node.js)的HashSet实现

原链接：https://code.google.com/p/jshashtable/wiki/HashSet

HashSet = function HashSet() {
    if (!(this instanceof HashSet))
        return;

    var _data = {};
    var _length = 0;
    var _DEFAULT = new Date();

    this.contains = function(val) {
        val = val.toString();
        return (!!_data[val] && _data.hasOwnProperty(val));
    };

    this.add = function(val) {
        if (!this.contains(val.toString())) {
            _length++;
        }
        _data[val.toString()] = val;
    };

    this.remove = function(val) {
        val = val.toString();
        if (!this.contains(val)) {
            return false;
        } else {
            delete _data[val.toString()];
            _length--;
            return true;
        }
    };

    this.clear = function() {
        for ( var val in _data) {
            if (_data.hasOwnProperty(val)) {
                delete _data[val];
            }
        }
        _length = 0;
    };

    this.isEmpty = function() {
        return (_length === 0);
    };

    this.size = function() {
        return _length;
    };

    this.toArray = function() {
        _data.length = _length;
        var arr = Array.prototype.slice.call(_data);
        delete _data.length;
        return arr;
    };
}
exports.HashSet = HashSet;