1 function Set() {
2 var items = {};
3 /**
4 * 添加元素
5 * @param {[type]} value [description]
6 */
7 this.add = function(value) {
8 if (!this.has(value)) {
9 items[value] = value;
10 return true;
11 }
12 return false;
13 };
14 /**
15 * 删除元素
16 * @param {[type]} value [description]
17 * @return {[type]} [description]
18 */
19 this.remove = function(value) {
20 if (this.has(value)) {
21 delete items[value];
22 return true;
23 }
24 return false;
25 };
26 /**
27 * 判断元素是否存在集合里
28 * @param {[type]} value [description]
29 * @return {Boolean} [description]
30 */
31 this.has = function(value) {
32 return items.hasOwnProperty(value);
33 };
34 /**
35 * 清空集合
36 * @return {[type]} [description]
37 */
38 this.clear = function() {
39 items = {};
40 };
41 /**
42 * 获取集合的长度
43 * @return {[type]} [description]
44 */
45 this.size = function() {
46 return Object.keys(items).length;
47 };
48 /**
49 * 获取集合的长度（兼容IE8）
50 * @return {[type]} [description]
51 */
52 this.sizeLegacy = function() {
53 var count = 0;
54 for (var prop in items) {
55 if (items.hasOwnProperty(prop))
56 ++count;
57 }
58 return count;
59 };
60 /**
61 * 获取集合
62 * @return {[type]} [description]
63 */
64 this.values = function() {
65 return Object.keys(items);
66 };
67 /**
68 * 获取集合（兼容IE8）
69 * @return {[type]} [description]
70 */
71 this.valuesLegacy = function() {
72 var keys = [];
73 for (var key in items) {
74 keys.push(key);
75 }
76 return keys;
77 };
78 /**
79 * 并集
80 * @param {[type]} otherSet [description]
81 * @return {[type]} [description]
82 */
83 this.union = function(otherSet) {
84 var unionSet = new Set();
85
86 var values = this.valuesLegacy();
87 for (var i = 0; i < values.length; i++) {
88 unionSet.add(values[i]);
89 }
90
91 values = otherSet.valuesLegacy();
92 for (var i = 0; i < values.length; i++) {
93 unionSet.add(values[i]);
94 }
95 return unionSet;
96 };
97 /**
98 * 交集
99 * @param {[type]} otherSet [description]
100 * @return {[type]} [description]
101 */
102 this.intersection = function(otherSet) {
103 var intersectionSet = new Set();
104
105 var values = this.valuesLegacy();
106 for (var i = 0; i < values.length; i++) {
107 if (otherSet.has(values[i])) {
108 intersectionSet.add(values[i]);
109 }
110 }
111
112 return intersectionSet;
113 };
114 /**
115 * 差集
116 * @param {[type]} otherSet [description]
117 * @return {[type]} [description]
118 */
119 this.difference = function(otherSet) {
120 var differenceSet = new Set();
121
122 var values = this.valuesLegacy();
123 for (var i = 0; i < values.length; i++) {
124 if (!otherSet.has(values[i]))
125 differenceSet.add(values[i]);
126 }
127 return differenceSet;
128 };
129 /**
130 * 子集
131 * @param {[type]} otherSet [description]
132 * @return {[type]} [description]
133 */
134 this.subset = function(otherSet) {
135 if (this.sizeLegacy() > otherSet.sizeLegacy()) {
136 return false;
137 } else {
138 var values = this.valuesLegacy();
139 for (var i = 0; i < values.length; i++) {
140 if (!otherSet.has(values[i])) {
141 return false;
142 }
143 }
144 return true;
145 }
146 }
147 }
148
149 var set = new Set();
150 set.add(1);
151 set.add(2);
152 set.add(3);
153
154 var set1 = new Set();
155 set1.add(3);
156 set1.add(4);
157 set1.add(5);
158
159 var set2 = new Set();
160 set2.add(3);
161
162 var unionSet = set.union(set1);
163 console.log(unionSet.valuesLegacy());
164
165 var intersectionSet = set.intersection(set1);
166 console.log(intersectionSet.valuesLegacy());
167
168 var differenceSet = set.difference(set1);
169 console.log(differenceSet.valuesLegacy());
170
171 console.log(set.subset(set1));
172 console.log(set2.subset(set));
