{"id":215,"date":"2025-01-02T21:11:00","date_gmt":"2025-01-02T13:11:00","guid":{"rendered":"https:\/\/mitongxue.cn\/?p=215"},"modified":"2026-06-04T21:50:31","modified_gmt":"2026-06-04T13:50:31","slug":"weakmap%e5%92%8cweakset","status":"publish","type":"post","link":"https:\/\/mitongxue.cn\/index.php\/2025\/01\/02\/weakmap%e5%92%8cweakset\/","title":{"rendered":"WeakMap\u548cWeakSet"},"content":{"rendered":"\n

Map<\/em> \u548c Object<\/em> \u7684\u533a\u522b<\/h3>\n\n\n\n

\u5173\u4e8e Map<\/em> \u548c Object<\/em> \u7684\u533a\u522b\uff0c\u53ef\u4ee5\u53c2\u9605\u4e0b\u8868\uff1a<\/p>\n\n\n\n

\"\"\/<\/figure>\n\n\n\n

WeakMap<\/em><\/h2>\n\n\n\n

WeakMap<\/em> \u8d77\u6e90\u4e8e Map<\/em>\uff0c\u56e0\u6b64\u5b83\u4eec\u5f7c\u6b64\u975e\u5e38\u76f8\u4f3c\u3002\u4f46\u662f\uff0cWeakMap<\/em> \u5177\u6709\u5f88\u5927\u7684\u4e0d\u540c\u3002<\/p>\n\n\n\n

WeakMap<\/em> \u7684\u540d\u5b57\u662f\u600e\u4e48\u6765\u7684\u5462\uff1f<\/p>\n\n\n\n

\u55ef\uff0c\u662f\u56e0\u4e3a\u5b83\u4e0e\u5b83\u7684\u5f15\u7528\u94fe\u63a5\u6240\u6307\u5411\u7684\u6570\u636e\u5bf9\u8c61\u7684\u8fde\u63a5\u6216\u5173\u7cfb\u6ca1\u6709 Map<\/em> \u7684\u8fde\u63a5\u6216\u5173\u7cfb\u90a3\u4e48\u5f3a\uff0c\u6240\u4ee5\u5b83\u662f\u5f31\u7684\u3002<\/p>\n\n\n\n

\u5dee\u5f02 1<\/em>\uff1akey<\/em> \u5fc5\u987b\u662f\u5bf9\u8c61<\/strong><\/p>\n\n\n\n

\u53ef\u4ee5\u5c06\u4efb\u4f55\u503c\u4f5c\u4e3a\u952e\u4f20\u5165 Map<\/em> \u5bf9\u8c61\uff0c\u4f46 WeakMap<\/em> \u4e0d\u540c\uff0c\u5b83\u53ea\u63a5\u53d7\u4e00\u4e2a\u5bf9\u8c61\u4f5c\u4e3a\u952e\uff0c\u5426\u5219\uff0c\u5b83\u5c06\u8fd4\u56de\u4e00\u4e2a\u9519\u8bef\u3002<\/p>\n\n\n\n

const John = { name: 'John' };
const weakMap = new WeakMap();
weakMap.set(John, 'student');
\/\/ WeakMap {{...} => \"student\"}
weakMap.set('john', 'student');
\/\/ Uncaught TypeError: Invalid value used as weak map key<\/code><\/pre>\n\n\n\n
\u5dee\u5f02 2<\/em>\uff1a\u5e76\u975e Map<\/em> \u4e2d\u7684\u6240\u6709\u65b9\u6cd5\u90fd\u652f\u6301<\/strong><\/p>\n\n\n\n
WeakMap<\/em> \u53ef\u4ee5\u4f7f\u7528\u7684\u65b9\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n
    \n
  • delete<\/em><\/li>\n\n\n\n
  • get<\/em><\/li>\n\n\n\n
  • has<\/em><\/li>\n\n\n\n
  • set<\/em><\/li>\n<\/ul>\n\n\n\n
    \u8fd8\u6709\u4e00\u4e2a\u6700\u5927\u7684\u4e0d\u540c\u662f WeakMap<\/em> \u4e0d\u652f\u6301\u8fed\u4ee3\u5bf9\u8c61\u7684\u65b9\u6cd5<\/strong>\u3002<\/p>\n\n\n\n
    \u5dee\u5f02 3<\/em>\uff1a\u5f53 GC<\/em> \u6e05\u7406\u5f15\u7528\u65f6\uff0c\u6570\u636e\u4f1a\u88ab\u5220\u9664<\/strong><\/p>\n\n\n\n
    \u8fd9\u662f\u548c Map<\/em> \u76f8\u6bd4\u6700\u5927\u7684\u4e0d\u540c\u3002<\/p>\n\n\n\n
    \u4f8b\u5982\uff1a<\/p>\n\n\n\n
    let John = { major: \"math\" };
    \u200b
    const map = new Map();
    const weakMap = new WeakMap();
    \u200b
    map.set(John, 'John');
    weakMap.set(John, 'John');
    \u200b
    John = null;
    \/* John \u88ab\u5783\u573e\u6536\u96c6 *\/<\/code><\/pre>\n\n\n\n
    \u5f53 John<\/em> \u5bf9\u8c61\u88ab\u5783\u573e\u56de\u6536\u65f6\uff0cMap<\/em> \u5bf9\u8c61\u5c06\u4fdd\u6301\u5f15\u7528\u94fe\u63a5\uff0c\u800c WeakMap<\/em> \u5bf9\u8c61\u5c06\u4e22\u5931\u94fe\u63a5\u3002<\/p>\n\n\n\n
    \u6240\u4ee5\u5f53\u4f60\u4f7f\u7528 WeakMap<\/em> \u65f6\uff0c\u4f60\u5e94\u8be5\u8003\u8651\u8fd9\u4e2a\u7279\u70b9\u3002<\/p>\n\n\n\n
    Set<\/em><\/h2>\n\n\n\n
    Set<\/em> \u4e5f\u975e\u5e38\u7c7b\u4f3c\u4e8e Map<\/em>\uff0c\u4f46\u662f Set<\/em> \u5bf9\u4e8e\u5355\u4e2a\u503c\u66f4\u6709\u7528\u3002<\/p>\n\n\n\n
    \u6dfb\u52a0\u5c5e\u6027<\/h3>\n\n\n\n
    \u4f7f\u7528 add<\/em> \u65b9\u6cd5\u53ef\u4ee5\u6dfb\u52a0\u5c5e\u6027\u3002<\/p>\n\n\n\n
    const set = new Set();
    \u200b
    set.add(1);
    set.add('john');
    set.add(BigInt(10));
    \/\/ Set(4) {1, \"john\", 10n}<\/code><\/pre>\n\n\n\n
    \u4e0e Map<\/em> \u4e00\u6837\uff0cSet<\/em> \u4e5f\u4e0d\u5141\u8bb8\u6dfb\u52a0\u76f8\u540c\u7684\u503c\u3002<\/p>\n\n\n\n
    \u5bf9\u4e8e\u539f\u59cb\u6570\u636e\u7c7b\u578b\uff08boolean\u3001number\u3001string\u3001null\u3001undefined<\/em>\uff09\uff0c\u5982\u679c\u50a8\u5b58\u76f8\u540c\u503c\u5219\u53ea\u4fdd\u5b58\u4e00\u4e2a\uff0c\u5bf9\u4e8e\u5f15\u7528\u7c7b\u578b,\u5f15\u7528\u5730\u5740\u5b8c\u5168\u76f8\u540c\u5219\u53ea\u4f1a\u5b58\u4e00\u4e2a\u3002<\/p>\n\n\n\n
      \n
    • +0<\/em> \u4e0e -0<\/em> \u5728\u5b58\u50a8\u5224\u65ad\u552f\u4e00\u6027\u7684\u65f6\u5019\u662f\u6052\u7b49\u7684\uff0c\u6240\u4ee5\u4e0d\u53ef\u4ee5\u91cd\u590d\u3002<\/li>\n\n\n\n
    • undefined<\/em> \u548c undefined<\/em> \u662f\u6052\u7b49\u7684\uff0c\u6240\u4ee5\u4e0d\u53ef\u4ee5\u91cd\u590d\u3002<\/li>\n\n\n\n
    • NaN<\/em> \u4e0e NaN<\/em> \u662f\u4e0d\u6052\u7b49\u7684\uff0c\u4f46\u662f\u5728 Set<\/em> \u4e2d\u53ea\u80fd\u5b58\u4e00\u4e2a\u4e0d\u80fd\u91cd\u590d\u3002<\/li>\n<\/ul>\n\n\n\n
      \u5e94\u7528\u573a\u666f<\/h3>\n\n\n\n
      \u63a5\u4e0b\u6765\u6765\u770b\u4e00\u4e0b Set<\/em> \u5e38\u89c1\u7684\u5e94\u7528\u573a\u666f\uff1a<\/p>\n\n\n\n
      \/\/\u6570\u7ec4\u53bb\u91cd
      ...new Set([1,1,2,2,3])
      \u200b
      \/\/\u5e76\u96c6
      var arr1 = [1, 2, 3]
      var arr2 = [2, 3, 4]
      var newArr = [...new Set([...arr1, ...arr2])]
      \/\/\u4ea4\u96c6
      var arr1 = [1, 2, 3]
      var arr2 = [2, 3, 4]
      var set1 = new Set(arr1)
      var set2 = new Set(arr2)
      var newArr = []
      set1.forEach(item => {
          set2.has(item) ? newArr.push(item) : ''
      })
      console.log(newArr)
      \/\/\u5dee\u96c6
      var arr1 = [1, 2, 3]
      var arr2 = [2, 3, 4]
      var set1 = new Set(arr1)
      var set2 = new Set(arr2)
      var newArr = []
      set1.forEach(item => {
          set2.has(item) ? '' : newArr.push(item)
      })
      set2.forEach(item => {
          set1.has(item) ? '' : newArr.push(item)
      })
      console.log(newArr)<\/code><\/pre>\n\n\n\n
      WeakSet<\/em><\/h2>\n\n\n\n
      WeakSet<\/em> \u548c Set<\/em> \u533a\u522b\u5982\u4e0b\uff1a<\/p>\n\n\n\n
        \n
      • WeakSet<\/em> \u53ea\u80fd\u50a8\u5b58\u5bf9\u8c61\u5f15\u7528\uff0c\u4e0d\u80fd\u5b58\u653e\u503c\uff0c\u800c Set<\/em> \u5bf9\u8c61\u90fd\u53ef\u4ee5<\/li>\n\n\n\n
      • WeakSet<\/em> \u5bf9\u8c61\u4e2d\u50a8\u5b58\u7684\u5bf9\u8c61\u503c\u90fd\u662f\u88ab\u5f31\u5f15\u7528\u7684\uff0c\u5373\u5783\u573e\u56de\u6536\u673a\u5236\u4e0d\u8003\u8651 WeakSet<\/em> \u5bf9\u8be5\u5bf9\u8c61\u7684\u5f15\u7528\uff0c\u5982\u679c\u6ca1\u6709\u5176\u4ed6\u7684\u53d8\u91cf\u6216\u8005\u5c5e\u6027\u5f15\u7528\u8fd9\u4e2a\u5bf9\u8c61\u503c\uff0c\u5219\u8fd9\u4e2a\u5bf9\u8c61\u5c06\u4f1a\u88ab\u5783\u573e\u56de\u6536\u6389\u3002\uff08\u4e0d\u8003\u8651\u8be5\u5bf9\u8c61\u8fd8\u5b58\u5728\u4e0e WeakSet<\/em> \u4e2d\uff09\uff0c\u6240\u4ee5 WeakSet<\/em> \u5bf9\u8c61\u91cc\u6709\u591a\u5c11\u4e2a\u6210\u5458\u5143\u7d20\uff0c\u53d6\u51b3\u4e8e\u5783\u573e\u56de\u6536\u673a\u5236\u6709\u6ca1\u6709\u8fd0\u884c\uff0c\u8fd0\u884c\u524d\u540e\u6210\u5458\u4e2a\u6570\u53ef\u80fd\u4e0d\u4e00\u81f4\uff0c\u904d\u5386\u7ed3\u675f\u4e4b\u540e\uff0c\u6709\u7684\u6210\u5458\u53ef\u80fd\u53d6\u4e0d\u5230\uff0c\u88ab\u5783\u573e\u56de\u6536\u4e86\u3002\u56e0\u6b64 ES6<\/em> \u89c4\u5b9a\uff0cWeakSet<\/em> \u5bf9\u8c61\u662f\u65e0\u6cd5\u88ab\u904d\u5386\u7684\uff0c\u4e5f\u6ca1\u6709\u529e\u6cd5\u62ff\u5230\u5b83\u5305\u542b\u7684\u6240\u6709\u5143\u7d20\u3002<\/li>\n<\/ul>\n\n\n\n
        WeakSet<\/em> \u80fd\u591f\u4f7f\u7528\u7684\u65b9\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n