{"id":673,"date":"2024-06-22T11:28:17","date_gmt":"2024-06-22T03:28:17","guid":{"rendered":"https:\/\/levin.ink\/?p=673"},"modified":"2024-06-22T11:28:17","modified_gmt":"2024-06-22T03:28:17","slug":"js-3-11-generator-%e9%ab%98%e7%ba%a7-iteration","status":"publish","type":"post","link":"https:\/\/levin.ink\/?p=673","title":{"rendered":"JS &#8211; 3-11 Generator, \u9ad8\u7ea7 iteration"},"content":{"rendered":"<h1>generator<\/h1>\n<p>\u5e38\u89c4\u51fd\u6570\u53ea\u4f1a\u8fd4\u56de\u4e00\u4e2a\u5355\u4e00\u503c\uff08\u6216\u8005\u4e0d\u8fd4\u56de\u4efb\u4f55\u503c\uff09\u3002<br \/>\n\u800c generator \u53ef\u4ee5\u6309\u9700\u4e00\u4e2a\u63a5\u4e00\u4e2a\u5730\u8fd4\u56de\uff08\u201cyield\u201d\uff09\u591a\u4e2a\u503c\u3002\u5b83\u4eec\u53ef\u4e0e\u00a0<a href=\"https:\/\/zh.javascript.info\/iterable\">iterable<\/a>\u00a0\u5b8c\u7f8e\u914d\u5408\u4f7f\u7528\uff0c\u4ece\u800c\u53ef\u4ee5\u8f7b\u677e\u5730\u521b\u5efa\u6570\u636e\u6d41\u3002<\/p>\n<h2>generator \u51fd\u6570<\/h2>\n<p>\u8981\u521b\u5efa\u4e00\u4e2a generator\uff0c\u6211\u4eec\u9700\u8981\u4e00\u4e2a\u7279\u6b8a\u7684\u8bed\u6cd5\u7ed3\u6784\uff1a<code>function*<\/code>\uff0c\u5373\u6240\u8c13\u7684 \u201cgenerator function\u201d\u3002<br \/>\n\u5b83\u770b\u8d77\u6765\u50cf\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js\">function* generateSequence() {\n  yield 1;\n  yield 2;\n  return 3;\n}\n<\/code><\/pre>\n<p>generator \u51fd\u6570\u4e0e\u5e38\u89c4\u51fd\u6570\u7684\u884c\u4e3a\u4e0d\u540c\u3002\u5728\u6b64\u7c7b\u51fd\u6570\u88ab\u8c03\u7528\u65f6\uff0c\u5b83\u4e0d\u4f1a\u8fd0\u884c\u5176\u4ee3\u7801\u3002\u800c\u662f\u8fd4\u56de\u4e00\u4e2a\u88ab\u79f0\u4e3a \u201cgenerator object\u201d \u7684\u7279\u6b8a\u5bf9\u8c61\uff0c\u6765\u7ba1\u7406\u6267\u884c\u6d41\u7a0b\u3002<br \/>\n\u6211\u4eec\u6765\u770b\u4e00\u4e2a\u4f8b\u5b50\uff1a<\/p>\n<pre><code class=\"language-js\">function* generateSequence() {\n  yield 1;\n  yield 2;\n  return 3;\n}\n\n\/\/ &quot;generator function&quot; \u521b\u5efa\u4e86\u4e00\u4e2a &quot;generator object&quot;\nlet generator = generateSequence();\nalert(generator); \/\/ [object Generator]\n<\/code><\/pre>\n<p>\u5230\u76ee\u524d\u4e3a\u6b62\uff0c\u4e0a\u9762\u8fd9\u6bb5\u4ee3\u7801\u4e2d\u7684\u00a0<strong>\u51fd\u6570\u4f53<\/strong>\u00a0\u4ee3\u7801\u8fd8\u6ca1\u6709\u5f00\u59cb\u6267\u884c\uff1a<br \/>\n\u4e00\u4e2a generator \u7684\u4e3b\u8981\u65b9\u6cd5\u5c31\u662f\u00a0<code>next()<\/code>\u3002\u5f53\u88ab\u8c03\u7528\u65f6\uff08\u8bd1\u6ce8\uff1a\u6307\u00a0<code>next()<\/code>\u00a0\u65b9\u6cd5\uff09\uff0c\u5b83\u4f1a\u6062\u590d\u4e0a\u56fe\u6240\u793a\u7684\u8fd0\u884c\uff0c\u6267\u884c\u76f4\u5230\u6700\u8fd1\u7684\u00a0<code>yield &lt;value&gt;<\/code>\u00a0\u8bed\u53e5\uff08<code>value<\/code>\u00a0\u53ef\u4ee5\u88ab\u7701\u7565\uff0c\u9ed8\u8ba4\u4e3a\u00a0<code>undefined<\/code>\uff09\u3002\u7136\u540e\u51fd\u6570\u6267\u884c\u6682\u505c\uff0c\u5e76\u5c06\u4ea7\u51fa\u7684\uff08yielded\uff09\u503c\u8fd4\u56de\u5230\u5916\u90e8\u4ee3\u7801\u3002<br \/>\n<code>next()<\/code>\u00a0\u7684\u7ed3\u679c\u59cb\u7ec8\u662f\u4e00\u4e2a\u5177\u6709\u4e24\u4e2a\u5c5e\u6027\u7684\u5bf9\u8c61\uff1a<\/p>\n<ul>\n<li><code>value<\/code>: \u4ea7\u51fa\u7684\uff08yielded\uff09\u7684\u503c\u3002<\/li>\n<li><code>done<\/code>: \u5982\u679c generator \u51fd\u6570\u5df2\u6267\u884c\u5b8c\u6210\u5219\u4e3a\u00a0<code>true<\/code>\uff0c\u5426\u5219\u4e3a\u00a0<code>false<\/code>\u3002<br \/>\n\u4f8b\u5982\uff0c\u6211\u4eec\u53ef\u4ee5\u521b\u5efa\u4e00\u4e2a generator \u5e76\u83b7\u53d6\u5176\u7b2c\u4e00\u4e2a\u4ea7\u51fa\u7684\uff08yielded\uff09\u503c\uff1a<\/li>\n<\/ul>\n<pre><code class=\"language-js\">function* generateSequence() {\n  yield 1;\n  yield 2;\n  return 3;\n}\n\nlet generator = generateSequence();\n\nlet one = generator.next();\n\nalert(JSON.stringify(one)); \/\/ {value: 1, done: false}\n<\/code><\/pre>\n<p>\u622a\u81f3\u76ee\u524d\uff0c\u6211\u4eec\u53ea\u83b7\u5f97\u4e86\u7b2c\u4e00\u4e2a\u503c\uff0c\u73b0\u5728\u51fd\u6570\u6267\u884c\u5904\u5728\u7b2c\u4e8c\u884c\uff1a<br \/>\n\u8ba9\u6211\u4eec\u518d\u6b21\u8c03\u7528\u00a0<code>generator.next()<\/code>\u3002\u4ee3\u7801\u6062\u590d\u6267\u884c\u5e76\u8fd4\u56de\u4e0b\u4e00\u4e2a\u00a0<code>yield<\/code>\u00a0\u7684\u503c\uff1a<\/p>\n<pre><code class=\"language-js\">let two = generator.next();\n\nalert(JSON.stringify(two)); \/\/ {value: 2, done: false}\n<\/code><\/pre>\n<p>\u5982\u679c\u6211\u4eec\u7b2c\u4e09\u6b21\u8c03\u7528\u00a0<code>generator.next()<\/code>\uff0c\u4ee3\u7801\u5c06\u4f1a\u6267\u884c\u5230\u00a0<code>return<\/code>\u00a0\u8bed\u53e5\uff0c\u6b64\u65f6\u5c31\u5b8c\u6210\u8fd9\u4e2a\u51fd\u6570\u7684\u6267\u884c\uff1a<\/p>\n<pre><code class=\"language-js\">let three = generator.next();\n\nalert(JSON.stringify(three)); \/\/ {value: 3, done: true}\n<\/code><\/pre>\n<p>\u73b0\u5728 generator \u6267\u884c\u5b8c\u6210\u3002\u6211\u4eec\u901a\u8fc7\u00a0<code>done:true<\/code>\u00a0\u53ef\u4ee5\u770b\u51fa\u6765\u8fd9\u4e00\u70b9\uff0c\u5e76\u4e14\u5c06\u00a0<code>value:3<\/code>\u00a0\u5904\u7406\u4e3a\u6700\u7ec8\u7ed3\u679c\u3002<br \/>\n\u518d\u5bf9\u00a0<code>generator.next()<\/code>\u00a0\u8fdb\u884c\u65b0\u7684\u8c03\u7528\u4e0d\u518d\u6709\u4efb\u4f55\u610f\u4e49\u3002\u5982\u679c\u6211\u4eec\u8fd9\u6837\u505a\uff0c\u5b83\u5c06\u8fd4\u56de\u76f8\u540c\u7684\u5bf9\u8c61\uff1a<code>{done: true}<\/code>\u3002<\/p>\n<blockquote>\n<p><code>function* f(\u2026)<\/code>\u00a0\u6216\u00a0<code>function *f(\u2026)<\/code>\uff1f<br \/>\n\u8fd9\u4e24\u79cd\u8bed\u6cd5\u90fd\u662f\u5bf9\u7684\u3002<br \/>\n\u4f46\u662f\u901a\u5e38\u66f4\u503e\u5411\u4e8e\u7b2c\u4e00\u79cd\u8bed\u6cd5\uff0c\u56e0\u4e3a\u661f\u53f7\u00a0<code>*<\/code>\u00a0\u8868\u793a\u5b83\u662f\u4e00\u4e2a generator \u51fd\u6570\uff0c\u5b83\u63cf\u8ff0\u7684\u662f\u51fd\u6570\u79cd\u7c7b\u800c\u4e0d\u662f\u540d\u79f0\uff0c\u56e0\u6b64\u00a0<code>*<\/code>\u00a0\u5e94\u8be5\u548c\u00a0<code>function<\/code>\u00a0\u5173\u952e\u5b57\u7d27\u8d34\u4e00\u8d77\u3002<\/p>\n<\/blockquote>\n<h2>generator \u662f\u53ef\u8fed\u4ee3\u7684<\/h2>\n<p>\u5f53\u4f60\u770b\u5230\u00a0<code>next()<\/code>\u00a0\u65b9\u6cd5\uff0c\u6216\u8bb8\u4f60\u5df2\u7ecf\u731c\u5230\u4e86 generator \u662f\u00a0<a href=\"https:\/\/zh.javascript.info\/iterable\">\u53ef\u8fed\u4ee3\uff08iterable\uff09<\/a>\u7684\u3002<br \/>\n\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u00a0<code>for..of<\/code>\u00a0\u5faa\u73af\u904d\u5386\u5b83\u6240\u6709\u7684\u503c\uff1a<\/p>\n<pre><code class=\"language-js\">function* generateSequence() {\n  yield 1;\n  yield 2;\n  return 3;\n}\n\nlet generator = generateSequence();\n\nfor(let value of generator) {\n  alert(value); \/\/ 1\uff0c\u7136\u540e\u662f 2\n}\n<\/code><\/pre>\n<p><code>for..of<\/code>\u00a0\u5199\u6cd5\u662f\u4e0d\u662f\u770b\u8d77\u6765\u6bd4\u00a0<code>.next().value<\/code>\u00a0\u4f18\u96c5\u591a\u4e86\uff1f<br \/>\n\u2026\u2026\u4f46\u662f\u8bf7\u6ce8\u610f\uff1a\u4e0a\u9762\u8fd9\u4e2a\u4f8b\u5b50\u4f1a\u5148\u663e\u793a\u00a0<code>1<\/code>\uff0c\u7136\u540e\u662f\u00a0<code>2<\/code>\uff0c\u7136\u540e\u5c31\u6ca1\u4e86\u3002\u5b83\u4e0d\u4f1a\u663e\u793a\u00a0<code>3<\/code>\uff01<br \/>\n\u8fd9\u662f\u56e0\u4e3a\u5f53\u00a0<code>done: true<\/code>\u00a0\u65f6\uff0c<code>for..of<\/code>\u00a0\u5faa\u73af\u4f1a\u5ffd\u7565\u6700\u540e\u4e00\u4e2a\u00a0<code>value<\/code>\u3002\u56e0\u6b64\uff0c\u5982\u679c\u6211\u4eec\u60f3\u8981\u901a\u8fc7\u00a0<code>for..of<\/code>\u00a0\u5faa\u73af\u663e\u793a\u6240\u6709\u7684\u7ed3\u679c\uff0c\u6211\u4eec\u5fc5\u987b\u4f7f\u7528\u00a0<code>yield<\/code>\u00a0\u8fd4\u56de\u5b83\u4eec\uff1a<\/p>\n<pre><code class=\"language-js\">function* generateSequence() {\n  yield 1;\n  yield 2;\n  yield 3;\n}\n\nlet generator = generateSequence();\n\nfor(let value of generator) {\n  alert(value); \/\/ 1\uff0c\u7136\u540e\u662f 2\uff0c\u7136\u540e\u662f 3\n}\n<\/code><\/pre>\n<p>\u56e0\u4e3a generator \u662f\u53ef\u8fed\u4ee3\u7684\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528 iterator \u7684\u6240\u6709\u76f8\u5173\u529f\u80fd\uff0c\u4f8b\u5982\uff1aspread \u8bed\u6cd5\u00a0<code>...<\/code>\uff1a<\/p>\n<pre><code class=\"language-js\">function* generateSequence() {\n  yield 1;\n  yield 2;\n  yield 3;\n}\n\nlet sequence = [0, ...generateSequence()];\n\nalert(sequence); \/\/ 0, 1, 2, 3\n<\/code><\/pre>\n<p>\u5728\u4e0a\u9762\u8fd9\u6bb5\u4ee3\u7801\u4e2d\uff0c<code>...generateSequence()<\/code>\u00a0\u5c06\u53ef\u8fed\u4ee3\u7684 generator \u5bf9\u8c61\u8f6c\u6362\u4e3a\u4e86\u4e00\u4e2a\u6570\u7ec4\uff08\u5173\u4e8e spread \u8bed\u6cd5\u7684\u66f4\u591a\u7ec6\u8282\u8bf7\u89c1\u00a0<a href=\"https:\/\/zh.javascript.info\/rest-parameters-spread#spread-syntax\">Rest \u53c2\u6570\u4e0e Spread \u8bed\u6cd5<\/a>\uff09\u3002<\/p>\n<h2>\u4f7f\u7528 generator \u8fdb\u884c\u8fed\u4ee3<\/h2>\n<p>\u5728\u524d\u9762\u7684\u00a0<a href=\"https:\/\/zh.javascript.info\/iterable\">Iterable object\uff08\u53ef\u8fed\u4ee3\u5bf9\u8c61\uff09<\/a>\u00a0\u4e00\u7ae0\u4e2d\uff0c\u6211\u4eec\u521b\u5efa\u4e86\u4e00\u4e2a\u53ef\u8fed\u4ee3\u7684\u00a0<code>range<\/code>\u00a0\u5bf9\u8c61\uff0c\u5b83\u8fd4\u56de\u00a0<code>from..to<\/code>\u00a0\u7684\u503c\u3002<br \/>\n\u73b0\u5728\uff0c\u6211\u4eec\u56de\u5fc6\u4e00\u4e0b\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"language-js\">let range = {\n  from: 1,\n  to: 5,\n\n  \/\/ for..of range \u5728\u4e00\u5f00\u59cb\u5c31\u8c03\u7528\u4e00\u6b21\u8fd9\u4e2a\u65b9\u6cd5\n  [Symbol.iterator]() {\n    \/\/ ...\u5b83\u8fd4\u56de iterator object\uff1a\n    \/\/ \u540e\u7eed\u7684\u64cd\u4f5c\u4e2d\uff0cfor..of \u5c06\u53ea\u9488\u5bf9\u8fd9\u4e2a\u5bf9\u8c61\uff0c\u5e76\u4f7f\u7528 next() \u5411\u5b83\u8bf7\u6c42\u4e0b\u4e00\u4e2a\u503c\n    return {\n      current: this.from,\n      last: this.to,\n\n      \/\/ for..of \u5faa\u73af\u5728\u6bcf\u6b21\u8fed\u4ee3\u65f6\u90fd\u4f1a\u8c03\u7528 next()\n      next() {\n        \/\/ \u5b83\u5e94\u8be5\u4ee5\u5bf9\u8c61 {done:.., value :...} \u7684\u5f62\u5f0f\u8fd4\u56de\u503c\n        if (this.current &lt;= this.last) {\n          return { done: false, value: this.current++ };\n        } else {\n          return { done: true };\n        }\n      }\n    };\n  }\n};\n\n\/\/ \u8fed\u4ee3\u6574\u4e2a range \u5bf9\u8c61\uff0c\u8fd4\u56de\u4ece `range.from` \u5230 `range.to` \u8303\u56f4\u7684\u6240\u6709\u6570\u5b57\nalert([...range]); \/\/ 1,2,3,4,5\n<\/code><\/pre>\n<p>\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u63d0\u4f9b\u4e00\u4e2a generator \u51fd\u6570\u4f5c\u4e3a\u00a0<code>Symbol.iterator<\/code>\uff0c\u6765\u4f7f\u7528 generator \u8fdb\u884c\u8fed\u4ee3\uff1a<br \/>\n\u4e0b\u9762\u662f\u4e00\u4e2a\u76f8\u540c\u7684\u00a0<code>range<\/code>\uff0c\u4f46\u7d27\u51d1\u5f97\u591a\uff1a<\/p>\n<pre><code class=\"language-js\">let range = {\n  from: 1,\n  to: 5,\n\n  *[Symbol.iterator]() { \/\/ [Symbol.iterator]: function*() \u7684\u7b80\u5199\u5f62\u5f0f\n    for(let value = this.from; value &lt;= this.to; value++) {\n      yield value;\n    }\n  }\n};\n\nalert( [...range] ); \/\/ 1,2,3,4,5\n<\/code><\/pre>\n<p>\u4e4b\u6240\u4ee5\u4ee3\u7801\u6b63\u5e38\u5de5\u4f5c\uff0c\u662f\u56e0\u4e3a\u00a0<code>range[Symbol.iterator]()<\/code>\u00a0\u73b0\u5728\u8fd4\u56de\u4e00\u4e2a generator\uff0c\u800c generator \u65b9\u6cd5\u6b63\u662f\u00a0<code>for..of<\/code>\u00a0\u6240\u671f\u671b\u7684\uff1a<\/p>\n<ul>\n<li>\u5b83\u5177\u6709\u00a0<code>.next()<\/code>\u00a0\u65b9\u6cd5<\/li>\n<li>\u5b83\u4ee5\u00a0<code>{value: ..., done: true\/false}<\/code>\u00a0\u7684\u5f62\u5f0f\u8fd4\u56de\u503c<br \/>\n\u5f53\u7136\uff0c\u8fd9\u4e0d\u662f\u5de7\u5408\u3002generator \u88ab\u6dfb\u52a0\u5230 JavaScript \u8bed\u8a00\u4e2d\u662f\u6709\u5bf9 iterator \u7684\u8003\u91cf\u7684\uff0c\u4ee5\u4fbf\u66f4\u5bb9\u6613\u5730\u5b9e\u73b0 iterator\u3002<br \/>\n\u5e26\u6709 generator \u7684\u53d8\u4f53\u6bd4\u539f\u6765\u7684\u00a0<code>range<\/code>\u00a0\u8fed\u4ee3\u4ee3\u7801\u7b80\u6d01\u5f97\u591a\uff0c\u5e76\u4e14\u4fdd\u6301\u4e86\u76f8\u540c\u7684\u529f\u80fd\u3002<\/li>\n<\/ul>\n<blockquote>\n<p>generator \u53ef\u4ee5\u6c38\u8fdc\u4ea7\u51fa\uff08yield\uff09\u503c<br \/>\n\u5728\u4e0a\u9762\u7684\u793a\u4f8b\u4e2d\uff0c\u6211\u4eec\u751f\u6210\u4e86\u6709\u9650\u5e8f\u5217\uff0c\u4f46\u662f\u6211\u4eec\u4e5f\u53ef\u4ee5\u521b\u5efa\u4e00\u4e2a\u751f\u6210\u65e0\u9650\u5e8f\u5217\u7684 generator\uff0c\u5b83\u53ef\u4ee5\u4e00\u76f4\u4ea7\u51fa\uff08yield\uff09\u503c\u3002\u4f8b\u5982\uff0c\u65e0\u5e8f\u7684\u4f2a\u968f\u673a\u6570\u5e8f\u5217\u3002<br \/>\n\u8fd9\u79cd\u60c5\u51b5\u4e0b\u80af\u5b9a\u9700\u8981\u5728 generator \u7684\u00a0<code>for..of<\/code>\u00a0\u5faa\u73af\u4e2d\u6dfb\u52a0\u4e00\u4e2a\u00a0<code>break<\/code>\uff08\u6216\u8005\u00a0<code>return<\/code>\uff09\u3002\u5426\u5219\u5faa\u73af\u5c06\u6c38\u8fdc\u91cd\u590d\u4e0b\u53bb\u5e76\u6302\u8d77\u3002<\/p>\n<\/blockquote>\n<h2>generator \u7ec4\u5408<\/h2>\n<p>generator \u7ec4\u5408\uff08composition\uff09\u662f generator \u7684\u4e00\u4e2a\u7279\u6b8a\u529f\u80fd\uff0c\u5b83\u5141\u8bb8\u900f\u660e\u5730\uff08transparently\uff09\u5c06 generator \u5f7c\u6b64\u201c\u5d4c\u5165\uff08embed\uff09\u201d\u5230\u4e00\u8d77\u3002<br \/>\n\u4f8b\u5982\uff0c\u6211\u4eec\u6709\u4e00\u4e2a\u751f\u6210\u6570\u5b57\u5e8f\u5217\u7684\u51fd\u6570\uff1a<\/p>\n<pre><code class=\"language-js\">function* generateSequence(start, end) {\n  for (let i = start; i &lt;= end; i++) yield i;\n}\n<\/code><\/pre>\n<p>\u73b0\u5728\uff0c\u6211\u4eec\u60f3\u91cd\u7528\u5b83\u6765\u751f\u6210\u4e00\u4e2a\u66f4\u590d\u6742\u7684\u5e8f\u5217\uff1a<\/p>\n<ul>\n<li>\u9996\u5148\u662f\u6570\u5b57\u00a0<code>0..9<\/code>\uff08\u5b57\u7b26\u4ee3\u7801\u4e3a 48\u202657\uff09\uff0c<\/li>\n<li>\u63a5\u4e0b\u6765\u662f\u5927\u5199\u5b57\u6bcd\u00a0<code>A..Z<\/code>\uff08\u5b57\u7b26\u4ee3\u7801\u4e3a 65\u202690\uff09<\/li>\n<li>\u63a5\u4e0b\u6765\u662f\u5c0f\u5199\u5b57\u6bcd\u00a0<code>a...z<\/code>\uff08\u5b57\u7b26\u4ee3\u7801\u4e3a 97\u2026122\uff09<br \/>\n\u6211\u4eec\u53ef\u4ee5\u5bf9\u8fd9\u4e2a\u5e8f\u5217\u8fdb\u884c\u5e94\u7528\uff0c\u4f8b\u5982\uff0c\u6211\u4eec\u53ef\u4ee5\u4ece\u8fd9\u4e2a\u5e8f\u5217\u4e2d\u9009\u62e9\u5b57\u7b26\u6765\u521b\u5efa\u5bc6\u7801\uff08\u4e5f\u53ef\u4ee5\u6dfb\u52a0\u8bed\u6cd5\u5b57\u7b26\uff09\uff0c\u4f46\u8ba9\u6211\u4eec\u5148\u751f\u6210\u5b83\u3002<br \/>\n\u5728\u5e38\u89c4\u51fd\u6570\u4e2d\uff0c\u8981\u5408\u5e76\u5176\u4ed6\u591a\u4e2a\u51fd\u6570\u7684\u7ed3\u679c\uff0c\u6211\u4eec\u9700\u8981\u8c03\u7528\u5b83\u4eec\uff0c\u5b58\u50a8\u5b83\u4eec\u7684\u7ed3\u679c\uff0c\u6700\u540e\u518d\u5c06\u5b83\u4eec\u5408\u5e76\u5230\u4e00\u8d77\u3002<br \/>\n\u5bf9\u4e8e generator \u800c\u8a00\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u00a0<code>yield*<\/code>\u00a0\u8fd9\u4e2a\u7279\u6b8a\u7684\u8bed\u6cd5\u6765\u5c06\u4e00\u4e2a generator \u201c\u5d4c\u5165\u201d\uff08\u7ec4\u5408\uff09\u5230\u53e6\u4e00\u4e2a generator \u4e2d\uff1a<br \/>\n\u7ec4\u5408\u7684 generator \u7684\u4f8b\u5b50\uff1a<\/li>\n<\/ul>\n<pre><code class=\"language-js\">function* generateSequence(start, end) {\n  for (let i = start; i &lt;= end; i++) yield i;\n}\n\nfunction* generatePasswordCodes() {\n\n  \/\/ 0..9\n  yield* generateSequence(48, 57);\n\n  \/\/ A..Z\n  yield* generateSequence(65, 90);\n\n  \/\/ a..z\n  yield* generateSequence(97, 122);\n\n}\n\nlet str = '';\n\nfor(let code of generatePasswordCodes()) {\n  str += String.fromCharCode(code);\n}\n\nalert(str); \/\/ 0..9A..Za..z\n<\/code><\/pre>\n<p><code>yield*<\/code>\u00a0\u6307\u4ee4\u5c06\u6267\u884c\u00a0<strong>\u59d4\u6258<\/strong>\u00a0\u7ed9\u53e6\u4e00\u4e2a generator\u3002\u8fd9\u4e2a\u672f\u8bed\u610f\u5473\u7740\u00a0<code>yield* gen<\/code>\u00a0\u5728 generator\u00a0<code>gen<\/code>\u00a0\u4e0a\u8fdb\u884c\u8fed\u4ee3\uff0c\u5e76\u5c06\u5176\u4ea7\u51fa\uff08yield\uff09\u7684\u503c\u900f\u660e\u5730\uff08transparently\uff09\u8f6c\u53d1\u5230\u5916\u90e8\u3002\u5c31\u597d\u50cf\u8fd9\u4e9b\u503c\u5c31\u662f\u7531\u5916\u90e8\u7684 generator yield \u7684\u4e00\u6837\u3002<br \/>\n\u6267\u884c\u7ed3\u679c\u4e0e\u6211\u4eec\u5185\u8054\u5d4c\u5957 generator \u4e2d\u7684\u4ee3\u7801\u83b7\u5f97\u7684\u7ed3\u679c\u76f8\u540c\uff1a<\/p>\n<pre><code class=\"language-js\">function* generateSequence(start, end) {\n  for (let i = start; i &lt;= end; i++) yield i;\n}\n\nfunction* generateAlphaNum() {\n\n  \/\/ yield* generateSequence(48, 57);\n  for (let i = 48; i &lt;= 57; i++) yield i;\n\n  \/\/ yield* generateSequence(65, 90);\n  for (let i = 65; i &lt;= 90; i++) yield i;\n\n  \/\/ yield* generateSequence(97, 122);\n  for (let i = 97; i &lt;= 122; i++) yield i;\n\n}\n\nlet str = '';\n\nfor(let code of generateAlphaNum()) {\n  str += String.fromCharCode(code);\n}\n\nalert(str); \/\/ 0..9A..Za..z\n<\/code><\/pre>\n<p>generator \u7ec4\u5408\uff08composition\uff09\u662f\u5c06\u4e00\u4e2a generator \u6d41\u63d2\u5165\u5230\u53e6\u4e00\u4e2a generator \u6d41\u7684\u81ea\u7136\u7684\u65b9\u5f0f\u3002\u5b83\u4e0d\u9700\u8981\u4f7f\u7528\u989d\u5916\u7684\u5185\u5b58\u6765\u5b58\u50a8\u4e2d\u95f4\u7ed3\u679c\u3002<\/p>\n<h2>yield \u662f\u4e00\u6761\u53cc\u5411\u8def<\/h2>\n<p>\u76ee\u524d\u770b\u6765\uff0cgenerator \u548c\u53ef\u8fed\u4ee3\u5bf9\u8c61\u7c7b\u4f3c\uff0c\u90fd\u5177\u6709\u7528\u6765\u751f\u6210\u503c\u7684\u7279\u6b8a\u8bed\u6cd5\u3002\u4f46\u5b9e\u9645\u4e0a\uff0cgenerator \u66f4\u52a0\u5f3a\u5927\u4e14\u7075\u6d3b\u3002<br \/>\n\u8fd9\u662f\u56e0\u4e3a\u00a0<code>yield<\/code>\u00a0\u662f\u4e00\u6761\u53cc\u5411\u8def\uff08two-way street\uff09\uff1a\u5b83\u4e0d\u4ec5\u53ef\u4ee5\u5411\u5916\u8fd4\u56de\u7ed3\u679c\uff0c\u800c\u4e14\u8fd8\u53ef\u4ee5\u5c06\u5916\u90e8\u7684\u503c\u4f20\u9012\u5230 generator \u5185\u3002<br \/>\n\u8c03\u7528\u00a0<code>generator.next(arg)<\/code>\uff0c\u6211\u4eec\u5c31\u80fd\u5c06\u53c2\u6570\u00a0<code>arg<\/code>\u00a0\u4f20\u9012\u5230 generator \u5185\u90e8\u3002\u8fd9\u4e2a\u00a0<code>arg<\/code>\u00a0\u53c2\u6570\u4f1a\u53d8\u6210\u00a0<code>yield<\/code>\u00a0\u7684\u7ed3\u679c\u3002<br \/>\n\u6211\u4eec\u6765\u770b\u4e00\u4e2a\u4f8b\u5b50\uff1a<\/p>\n<pre><code class=\"language-js\">function* gen() {\n  \/\/ \u5411\u5916\u90e8\u4ee3\u7801\u4f20\u9012\u4e00\u4e2a\u95ee\u9898\u5e76\u7b49\u5f85\u7b54\u6848\n  let result = yield &quot;2 + 2 = ?&quot;; \/\/ (*)\n\n  alert(result);\n}\n\nlet generator = gen();\n\nlet question = generator.next().value; \/\/ &lt;-- yield \u8fd4\u56de\u7684 value\n\ngenerator.next(4); \/\/ --&gt; \u5c06\u7ed3\u679c\u4f20\u9012\u5230 generator \u4e2d\n<\/code><\/pre>\n<p><img decoding=\"async\" src=\"https:\/\/levin.ink\/wp-content\/uploads\/2024\/06\/Pasted-image-20240622095709.png\" alt=\"Pasted image 20240622095709.png\"><\/p>\n<ol>\n<li>\u7b2c\u4e00\u6b21\u8c03\u7528\u00a0<code>generator.next()<\/code>\u00a0\u5e94\u8be5\u662f\u4e0d\u5e26\u53c2\u6570\u7684\uff08\u5982\u679c\u5e26\u53c2\u6570\uff0c\u90a3\u4e48\u8be5\u53c2\u6570\u4f1a\u88ab\u5ffd\u7565\uff09\u3002\u5b83\u5f00\u59cb\u6267\u884c\u5e76\u8fd4\u56de\u7b2c\u4e00\u4e2a\u00a0<code>yield &quot;2 + 2 = ?&quot;<\/code>\u00a0\u7684\u7ed3\u679c\u3002\u6b64\u65f6\uff0cgenerator \u6267\u884c\u6682\u505c\uff0c\u800c\u505c\u7559\u5728\u00a0<code>(*)<\/code>\u00a0\u884c\u4e0a\u3002<\/li>\n<li>\u7136\u540e\uff0c\u6b63\u5982\u4e0a\u9762\u56fe\u7247\u4e2d\u663e\u793a\u7684\u90a3\u6837\uff0c<code>yield<\/code>\u00a0\u7684\u7ed3\u679c\u8fdb\u5165\u8c03\u7528\u4ee3\u7801\u4e2d\u7684\u00a0<code>question<\/code>\u00a0\u53d8\u91cf\u3002<\/li>\n<li>\u5728\u00a0<code>generator.next(4)<\/code>\uff0cgenerator \u6062\u590d\u6267\u884c\uff0c\u5e76\u83b7\u5f97\u4e86\u00a0<code>4<\/code>\u00a0\u4f5c\u4e3a\u7ed3\u679c\uff1a<code>let result = 4<\/code>\u3002<br \/>\n\u8bf7\u6ce8\u610f\uff0c\u5916\u90e8\u4ee3\u7801\u4e0d\u5fc5\u7acb\u5373\u8c03\u7528\u00a0<code>next(4)<\/code>\u3002\u5916\u90e8\u4ee3\u7801\u53ef\u80fd\u9700\u8981\u4e00\u4e9b\u65f6\u95f4\u3002\u8fd9\u6ca1\u95ee\u9898\uff1agenerator \u5c06\u7b49\u5f85\u5b83\u3002<br \/>\n\u4f8b\u5982\uff1a<\/li>\n<\/ol>\n<pre><code class=\"language-js\">\/\/ \u4e00\u6bb5\u65f6\u95f4\u540e\u6062\u590d generator\nsetTimeout(() =&gt; generator.next(4), 1000);\n<\/code><\/pre>\n<p>\u6211\u4eec\u53ef\u4ee5\u770b\u5230\uff0c\u4e0e\u5e38\u89c4\u51fd\u6570\u4e0d\u540c\uff0cgenerator \u548c\u8c03\u7528 generator \u7684\u4ee3\u7801\u53ef\u4ee5\u901a\u8fc7\u5728\u00a0<code>next\/yield<\/code>\u00a0\u4e2d\u4f20\u9012\u503c\u6765\u4ea4\u6362\u7ed3\u679c\u3002<br \/>\n\u4e3a\u4e86\u8bb2\u5f97\u66f4\u6d45\u663e\u6613\u61c2\uff0c\u6211\u4eec\u6765\u770b\u53e6\u4e00\u4e2a\u4f8b\u5b50\uff0c\u5176\u4e2d\u5305\u542b\u4e86\u8bb8\u591a\u8c03\u7528\uff1a<\/p>\n<pre><code class=\"language-js\">function* gen() {\n  let ask1 = yield &quot;2 + 2 = ?&quot;;\n\n  alert(ask1); \/\/ 4\n\n  let ask2 = yield &quot;3 * 3 = ?&quot;\n\n  alert(ask2); \/\/ 9\n}\n\nlet generator = gen();\n\nalert( generator.next().value ); \/\/ &quot;2 + 2 = ?&quot;\n\nalert( generator.next(4).value ); \/\/ &quot;3 * 3 = ?&quot;\n\nalert( generator.next(9).done ); \/\/ true\n<\/code><\/pre>\n<p><img decoding=\"async\" src=\"https:\/\/levin.ink\/wp-content\/uploads\/2024\/06\/Pasted-image-20240622095856.png\" alt=\"Pasted image 20240622095856.png\"><\/p>\n<ol>\n<li>\u7b2c\u4e00\u4e2a\u00a0<code>.next()<\/code>\u00a0\u542f\u52a8\u4e86 generator \u7684\u6267\u884c\u2026\u2026\u6267\u884c\u5230\u8fbe\u7b2c\u4e00\u4e2a\u00a0<code>yield<\/code>\u3002<\/li>\n<li>\u7ed3\u679c\u88ab\u8fd4\u56de\u5230\u5916\u90e8\u4ee3\u7801\u4e2d\u3002<\/li>\n<li>\u7b2c\u4e8c\u4e2a\u00a0<code>.next(4)<\/code>\u00a0\u5c06\u00a0<code>4<\/code>\u00a0\u4f5c\u4e3a\u7b2c\u4e00\u4e2a\u00a0<code>yield<\/code>\u00a0\u7684\u7ed3\u679c\u4f20\u9012\u56de generator \u5e76\u6062\u590d generator \u7684\u6267\u884c\u3002<\/li>\n<li>\u2026\u2026\u6267\u884c\u5230\u8fbe\u7b2c\u4e8c\u4e2a\u00a0<code>yield<\/code>\uff0c\u5b83\u53d8\u6210\u4e86 generator \u8c03\u7528\u7684\u7ed3\u679c\u3002<\/li>\n<li>\u7b2c\u4e09\u4e2a\u00a0<code>next(9)<\/code>\u00a0\u5c06\u00a0<code>9<\/code>\u00a0\u4f5c\u4e3a\u7b2c\u4e8c\u4e2a\u00a0<code>yield<\/code>\u00a0\u7684\u7ed3\u679c\u4f20\u5165 generator \u5e76\u6062\u590d generator \u7684\u6267\u884c\uff0c\u6267\u884c\u73b0\u5728\u5230\u8fbe\u4e86\u51fd\u6570\u7684\u6700\u5e95\u90e8\uff0c\u6240\u4ee5\u8fd4\u56de\u00a0<code>done: true<\/code>\u3002<br \/>\n\u8fd9\u4e2a\u8fc7\u7a0b\u5c31\u50cf\u201c\u4e52\u4e53\u7403\u201d\u6e38\u620f\u3002\u6bcf\u4e2a\u00a0<code>next(value)<\/code>\uff08\u9664\u4e86\u7b2c\u4e00\u4e2a\uff09\u4f20\u9012\u4e00\u4e2a\u503c\u5230 generator \u4e2d\uff0c\u8be5\u503c\u53d8\u6210\u4e86\u5f53\u524d\u00a0<code>yield<\/code>\u00a0\u7684\u7ed3\u679c\uff0c\u7136\u540e\u83b7\u53d6\u4e0b\u4e00\u4e2a\u00a0<code>yield<\/code>\u00a0\u7684\u7ed3\u679c\u3002<\/li>\n<\/ol>\n<h2>generator.throw<\/h2>\n<p>\u6b63\u5982\u6211\u4eec\u5728\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\u89c2\u5bdf\u5230\u7684\u90a3\u6837\uff0c\u5916\u90e8\u4ee3\u7801\u53ef\u80fd\u4f1a\u5c06\u4e00\u4e2a\u503c\u4f20\u9012\u5230 generator\uff0c\u4f5c\u4e3a\u00a0<code>yield<\/code>\u00a0\u7684\u7ed3\u679c\u3002<br \/>\n\u2026\u2026\u4f46\u662f\u5b83\u4e5f\u53ef\u4ee5\u5728\u90a3\u91cc\u53d1\u8d77\uff08\u629b\u51fa\uff09\u4e00\u4e2a error\u3002\u8fd9\u5f88\u81ea\u7136\uff0c\u56e0\u4e3a error \u672c\u8eab\u4e5f\u662f\u4e00\u79cd\u7ed3\u679c\u3002<br \/>\n\u8981\u5411\u00a0<code>yield<\/code>\u00a0\u4f20\u9012\u4e00\u4e2a error\uff0c\u6211\u4eec\u5e94\u8be5\u8c03\u7528\u00a0<code>generator.throw(err)<\/code>\u3002\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c<code>err<\/code>\u00a0\u5c06\u88ab\u629b\u5230\u5bf9\u5e94\u7684\u00a0<code>yield<\/code>\u00a0\u6240\u5728\u7684\u90a3\u4e00\u884c\u3002<br \/>\n\u4f8b\u5982\uff0c<code>&quot;2 + 2?&quot;<\/code>\u00a0\u7684 yield \u5bfc\u81f4\u4e86\u4e00\u4e2a error\uff1a<\/p>\n<pre><code class=\"language-js\">function* gen() {\n  try {\n    let result = yield &quot;2 + 2 = ?&quot;; \/\/ (1)\n\n    alert(&quot;The execution does not reach here, because the exception is thrown above&quot;);\n  } catch(e) {\n    alert(e); \/\/ \u663e\u793a\u8fd9\u4e2a error\n  }\n}\n\nlet generator = gen();\n\nlet question = generator.next().value;\n\ngenerator.throw(new Error(&quot;The answer is not found in my database&quot;)); \/\/ (2)\n<\/code><\/pre>\n<p>\u5728\u00a0<code>(2)<\/code>\u00a0\u884c\u5f15\u5165\u5230 generator \u7684 error \u5bfc\u81f4\u4e86\u5728\u00a0<code>(1)<\/code>\u00a0\u884c\u4e2d\u7684\u00a0<code>yield<\/code>\u00a0\u51fa\u73b0\u4e86\u4e00\u4e2a\u5f02\u5e38\u3002\u5728\u4e0a\u9762\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c<code>try..catch<\/code>\u00a0\u6355\u83b7\u5e76\u663e\u793a\u4e86\u8fd9\u4e2a error\u3002<br \/>\n\u5982\u679c\u6211\u4eec\u6ca1\u6709\u6355\u83b7\u5b83\uff0c\u90a3\u4e48\u5c31\u4f1a\u50cf\u5176\u4ed6\u7684\u5f02\u5e38\u4e00\u6837\uff0c\u5b83\u5c06\u4ece generator \u201c\u6389\u51fa\u201d\u5230\u8c03\u7528\u4ee3\u7801\u4e2d\u3002<br \/>\n\u8c03\u7528\u4ee3\u7801\u7684\u5f53\u524d\u884c\u662f\u00a0<code>generator.throw<\/code>\u00a0\u6240\u5728\u7684\u90a3\u4e00\u884c\uff0c\u6807\u8bb0\u4e3a\u00a0<code>(2)<\/code>\u3002\u6240\u4ee5\u6211\u4eec\u53ef\u4ee5\u5728\u8fd9\u91cc\u6355\u83b7\u5b83\uff0c\u5c31\u50cf\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js\">function* generate() {\n  let result = yield &quot;2 + 2 = ?&quot;; \/\/ \u8fd9\u884c\u51fa\u73b0 error\n}\n\nlet generator = generate();\n\nlet question = generator.next().value;\n\ntry {\n  generator.throw(new Error(&quot;The answer is not found in my database&quot;));\n} catch(e) {\n  alert(e); \/\/ \u663e\u793a\u8fd9\u4e2a error\n}\n<\/code><\/pre>\n<p>\u5982\u679c\u6211\u4eec\u6ca1\u6709\u5728\u90a3\u91cc\u6355\u83b7\u8fd9\u4e2a error\uff0c\u90a3\u4e48\uff0c\u901a\u5e38\uff0c\u5b83\u4f1a\u6389\u5165\u5916\u90e8\u8c03\u7528\u4ee3\u7801\uff08\u5982\u679c\u6709\uff09\uff0c\u5982\u679c\u5728\u5916\u90e8\u4e5f\u6ca1\u6709\u88ab\u6355\u83b7\uff0c\u5219\u4f1a\u6740\u6b7b\u811a\u672c\u3002<\/p>\n<h2>generator.return<\/h2>\n<p><code>generator.return(value)<\/code>\u00a0\u5b8c\u6210 generator \u7684\u6267\u884c\u5e76\u8fd4\u56de\u7ed9\u5b9a\u7684\u00a0<code>value<\/code>\u3002<\/p>\n<pre><code class=\"language-js\">function* gen() {\n  yield 1;\n  yield 2;\n  yield 3;\n}\n\nconst g = gen();\n\ng.next();        \/\/ { value: 1, done: false }\ng.return('foo'); \/\/ { value: &quot;foo&quot;, done: true }\ng.next();        \/\/ { value: undefined, done: true }\n<\/code><\/pre>\n<p>\u5982\u679c\u6211\u4eec\u5728\u5df2\u5b8c\u6210\u7684 generator \u4e0a\u518d\u6b21\u4f7f\u7528\u00a0<code>generator.return()<\/code>\uff0c\u5b83\u5c06\u518d\u6b21\u8fd4\u56de\u8be5\u503c\uff08<a href=\"https:\/\/developer.mozilla.org\/en-US\/docs\/Web\/JavaScript\/Reference\/Global_Objects\/Generator\/return\">MDN<\/a>\uff09\u3002<br \/>\n\u901a\u5e38\u6211\u4eec\u4e0d\u4f7f\u7528\u5b83\uff0c\u56e0\u4e3a\u5927\u591a\u6570\u65f6\u5019\u6211\u4eec\u60f3\u8981\u83b7\u53d6\u6240\u6709\u7684\u8fd4\u56de\u503c\uff0c\u4f46\u662f\u5f53\u6211\u4eec\u60f3\u8981\u5728\u7279\u5b9a\u6761\u4ef6\u4e0b\u505c\u6b62 generator \u65f6\u5b83\u4f1a\u5f88\u6709\u7528\u3002<\/p>\n<h1>\u5f02\u6b65\u8fed\u4ee3\u548c generator<\/h1>\n<p>\u5f02\u6b65\u8fed\u4ee3\u5141\u8bb8\u6211\u4eec\u5bf9\u6309\u9700\u901a\u8fc7\u5f02\u6b65\u8bf7\u6c42\u800c\u5f97\u5230\u7684\u6570\u636e\u8fdb\u884c\u8fed\u4ee3\u3002\u4f8b\u5982\uff0c\u6211\u4eec\u901a\u8fc7\u7f51\u7edc\u5206\u6bb5\uff08chunk-by-chunk\uff09\u4e0b\u8f7d\u6570\u636e\u65f6\u3002\u5f02\u6b65\u751f\u6210\u5668\uff08generator\uff09\u4f7f\u8fd9\u4e00\u6b65\u9aa4\u66f4\u52a0\u65b9\u4fbf\u3002<br \/>\n\u9996\u5148\uff0c\u8ba9\u6211\u4eec\u6765\u770b\u4e00\u4e2a\u7b80\u5355\u7684\u793a\u4f8b\u4ee5\u638c\u63e1\u8bed\u6cd5\uff0c\u7136\u540e\u518d\u770b\u4e00\u4e2a\u5b9e\u9645\u7528\u4f8b\u3002<\/p>\n<h2>\u56de\u987e\u53ef\u8fed\u4ee3\u5bf9\u8c61<\/h2>\n<p>\u8ba9\u6211\u4eec\u56de\u987e\u4e00\u4e0b\u53ef\u8fed\u4ee3\u5bf9\u8c61\u7684\u76f8\u5173\u5185\u5bb9\u3002<br \/>\n\u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u5bf9\u8c61\uff0c\u4f8b\u5982\u4e0b\u9762\u7684\u00a0<code>range<\/code>\uff1a<\/p>\n<pre><code class=\"language-js\">let range = {\n  from: 1,\n  to: 5\n};\n<\/code><\/pre>\n<p>\u6211\u4eec\u60f3\u5bf9\u5b83\u4f7f\u7528\u00a0<code>for..of<\/code>\u00a0\u5faa\u73af\uff0c\u4f8b\u5982\u00a0<code>for(value of range)<\/code>\uff0c\u6765\u83b7\u53d6\u4ece\u00a0<code>1<\/code>\u00a0\u5230\u00a0<code>5<\/code>\u00a0\u7684\u503c\u3002<br \/>\n\u6362\u53e5\u8bdd\u8bf4\uff0c\u6211\u4eec\u60f3\u5411\u5bf9\u8c61\u00a0<code>range<\/code>\u00a0\u6dfb\u52a0\u00a0<strong>\u8fed\u4ee3\u80fd\u529b<\/strong>\u3002<br \/>\n\u8fd9\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528\u4e00\u4e2a\u540d\u4e3a\u00a0<code>Symbol.iterator<\/code>\u00a0\u7684\u7279\u6b8a\u65b9\u6cd5\u6765\u5b9e\u73b0\uff1a<\/p>\n<ul>\n<li>\u5f53\u5faa\u73af\u5f00\u59cb\u65f6\uff0c\u8be5\u65b9\u6cd5\u88ab\u00a0<code>for..of<\/code>\u00a0\u7ed3\u6784\u8c03\u7528\uff0c\u5e76\u4e14\u5b83\u5e94\u8be5\u8fd4\u56de\u4e00\u4e2a\u5e26\u6709\u00a0<code>next<\/code>\u00a0\u65b9\u6cd5\u7684\u5bf9\u8c61\u3002<\/li>\n<li>\u5bf9\u4e8e\u6bcf\u6b21\u8fed\u4ee3\uff0c\u90fd\u4f1a\u4e3a\u4e0b\u4e00\u4e2a\u503c\u8c03\u7528\u00a0<code>next()<\/code>\u00a0\u65b9\u6cd5\u3002<\/li>\n<li><code>next()<\/code>\u00a0\u65b9\u6cd5\u5e94\u8be5\u4ee5\u00a0<code>{done: true\/false, value:&lt;loop value&gt;}<\/code>\u00a0\u7684\u683c\u5f0f\u8fd4\u56de\u4e00\u4e2a\u503c\uff0c\u5176\u4e2d\u00a0<code>done:true<\/code>\u00a0\u8868\u793a\u5faa\u73af\u7ed3\u675f\u3002<br \/>\n\u8fd9\u662f\u53ef\u8fed\u4ee3\u7684\u00a0<code>range<\/code>\u00a0\u7684\u4e00\u4e2a\u5b9e\u73b0\uff1a<\/li>\n<\/ul>\n<pre><code class=\"language-js\">let range = {\n  from: 1,\n  to: 5,\n\n  [Symbol.iterator]() { \/\/ \u5728 for..of \u5faa\u73af\u5f00\u59cb\u65f6\u88ab\u8c03\u7528\u4e00\u6b21\n    return {\n      current: this.from,\n      last: this.to,\n\n      next() { \/\/ \u6bcf\u6b21\u8fed\u4ee3\u65f6\u90fd\u4f1a\u88ab\u8c03\u7528\uff0c\u6765\u83b7\u53d6\u4e0b\u4e00\u4e2a\u503c\n        if (this.current &lt;= this.last) {\n          return { done: false, value: this.current++ };\n        } else {\n          return { done: true };\n        }\n      }\n    };\n  }\n};\n\nfor(let value of range) {\n  alert(value); \/\/ 1\uff0c\u7136\u540e 2\uff0c\u7136\u540e 3\uff0c\u7136\u540e 4\uff0c\u7136\u540e 5\n}\n<\/code><\/pre>\n<h2>\u5f02\u6b65\u53ef\u8fed\u4ee3\u5bf9\u8c61<\/h2>\n<p>\u5f53\u503c\u662f\u4ee5\u5f02\u6b65\u7684\u5f62\u5f0f\u51fa\u73b0\u65f6\uff0c\u4f8b\u5982\u5728\u00a0<code>setTimeout<\/code>\u00a0\u6216\u8005\u53e6\u4e00\u79cd\u5ef6\u8fdf\u4e4b\u540e\uff0c\u5c31\u9700\u8981\u5f02\u6b65\u8fed\u4ee3\u3002<br \/>\n\u6700\u5e38\u89c1\u7684\u573a\u666f\u662f\uff0c\u5bf9\u8c61\u9700\u8981\u53d1\u9001\u4e00\u4e2a\u7f51\u7edc\u8bf7\u6c42\u4ee5\u4f20\u9012\u4e0b\u4e00\u4e2a\u503c\uff0c\u7a0d\u540e\u6211\u4eec\u5c06\u770b\u5230\u4e00\u4e2a\u5b83\u7684\u771f\u5b9e\u793a\u4f8b\u3002<br \/>\n\u8981\u4f7f\u5bf9\u8c61\u5f02\u6b65\u8fed\u4ee3\uff1a<\/p>\n<ol>\n<li>\u4f7f\u7528\u00a0<code>Symbol.asyncIterator<\/code>\u00a0\u53d6\u4ee3\u00a0<code>Symbol.iterator<\/code>\u3002<\/li>\n<li><code>next()<\/code>\u00a0\u65b9\u6cd5\u5e94\u8be5\u8fd4\u56de\u4e00\u4e2a\u00a0<code>promise<\/code>\uff08\u5e26\u6709\u4e0b\u4e00\u4e2a\u503c\uff0c\u5e76\u4e14\u72b6\u6001\u4e3a\u00a0<code>fulfilled<\/code>\uff09\u3002\n<ul>\n<li>\u5173\u952e\u5b57\u00a0<code>async<\/code>\u00a0\u53ef\u4ee5\u5b9e\u73b0\u8fd9\u4e00\u70b9\uff0c\u6211\u4eec\u53ef\u4ee5\u7b80\u5355\u5730\u4f7f\u7528\u00a0<code>async next()<\/code>\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u6211\u4eec\u5e94\u8be5\u4f7f\u7528\u00a0<code>for await (let item of iterable)<\/code>\u00a0\u5faa\u73af\u6765\u8fed\u4ee3\u8fd9\u6837\u7684\u5bf9\u8c61\u3002\n<ul>\n<li>\u6ce8\u610f\u5173\u952e\u5b57\u00a0<code>await<\/code>\u3002<br \/>\n\u4f5c\u4e3a\u5f00\u59cb\u7684\u793a\u4f8b\uff0c\u8ba9\u6211\u4eec\u521b\u5efa\u4e00\u4e2a\u53ef\u8fed\u4ee3\u7684\u00a0<code>range<\/code>\u00a0\u5bf9\u8c61\uff0c\u4e0e\u524d\u9762\u7684\u90a3\u4e2a\u7c7b\u4f3c\uff0c\u4e0d\u8fc7\u73b0\u5728\u5b83\u5c06\u5f02\u6b65\u5730\u6bcf\u79d2\u8fd4\u56de\u4e00\u4e2a\u503c\u3002<br \/>\n\u6211\u4eec\u9700\u8981\u505a\u7684\u5c31\u662f\u5bf9\u4e0a\u9762\u4ee3\u7801\u4e2d\u7684\u90e8\u5206\u4ee3\u7801\u8fdb\u884c\u66ff\u6362\uff1a<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<pre><code class=\"language-js\">let range = {\n  from: 1,\n  to: 5,\n\n  [Symbol.asyncIterator]() { \/\/ (1)\n    return {\n      current: this.from,\n      last: this.to,\n\n      async next() { \/\/ (2)\n\n        \/\/ \u6ce8\u610f\uff1a\u6211\u4eec\u53ef\u4ee5\u5728 async next \u5185\u90e8\u4f7f\u7528 &quot;await&quot;\n        await new Promise(resolve =&gt; setTimeout(resolve, 1000)); \/\/ (3)\n\n        if (this.current &lt;= this.last) {\n          return { done: false, value: this.current++ };\n        } else {\n          return { done: true };\n        }\n      }\n    };\n  }\n};\n\n(async () =&gt; {\n\n  for await (let value of range) { \/\/ (4)\n    alert(value); \/\/ 1,2,3,4,5\n  }\n\n})()\n<\/code><\/pre>\n<p>\u6b63\u5982\u6211\u4eec\u6240\u770b\u5230\u7684\uff0c\u5176\u7ed3\u6784\u4e0e\u5e38\u89c4\u7684 iterator \u7c7b\u4f3c:<\/p>\n<ol>\n<li>\u4e3a\u4e86\u4f7f\u4e00\u4e2a\u5bf9\u8c61\u53ef\u4ee5\u5f02\u6b65\u8fed\u4ee3\uff0c\u5b83\u5fc5\u987b\u5177\u6709\u65b9\u6cd5\u00a0<code>Symbol.asyncIterator<\/code>\u00a0<code>(1)<\/code>\u3002<\/li>\n<li>\u8fd9\u4e2a\u65b9\u6cd5\u5fc5\u987b\u8fd4\u56de\u4e00\u4e2a\u5e26\u6709\u00a0<code>next()<\/code>\u00a0\u65b9\u6cd5\u7684\u5bf9\u8c61\uff0c<code>next()<\/code>\u00a0\u65b9\u6cd5\u4f1a\u8fd4\u56de\u4e00\u4e2a promise\u00a0<code>(2)<\/code>\u3002<\/li>\n<li>\u8fd9\u4e2a\u00a0<code>next()<\/code>\u00a0\u65b9\u6cd5\u53ef\u4ee5\u4e0d\u662f\u00a0<code>async<\/code>\u00a0\u7684\uff0c\u5b83\u53ef\u4ee5\u662f\u4e00\u4e2a\u8fd4\u56de\u503c\u662f\u4e00\u4e2a\u00a0<code>promise<\/code>\u00a0\u7684\u5e38\u89c4\u7684\u65b9\u6cd5\uff0c\u4f46\u662f\u4f7f\u7528\u00a0<code>async<\/code>\u00a0\u5173\u952e\u5b57\u53ef\u4ee5\u5141\u8bb8\u6211\u4eec\u5728\u65b9\u6cd5\u5185\u90e8\u4f7f\u7528\u00a0<code>await<\/code>\uff0c\u6240\u4ee5\u4f1a\u66f4\u52a0\u65b9\u4fbf\u3002\u8fd9\u91cc\u6211\u4eec\u53ea\u662f\u7528\u4e8e\u5ef6\u8fdf 1 \u79d2\u7684\u64cd\u4f5c\u00a0<code>(3)<\/code>\u3002<\/li>\n<li>\u6211\u4eec\u4f7f\u7528\u00a0<code>for await(let value of range)<\/code>\u00a0<code>(4)<\/code>\u00a0\u6765\u8fdb\u884c\u8fed\u4ee3\uff0c\u4e5f\u5c31\u662f\u5728\u00a0<code>for<\/code>\u00a0\u540e\u9762\u6dfb\u52a0\u00a0<code>await<\/code>\u3002\u5b83\u4f1a\u8c03\u7528\u4e00\u6b21\u00a0<code>range[Symbol.asyncIterator]()<\/code>\u00a0\u65b9\u6cd5\u4e00\u6b21\uff0c\u7136\u540e\u8c03\u7528\u5b83\u7684\u00a0<code>next()<\/code>\u00a0\u65b9\u6cd5\u83b7\u53d6\u503c\u3002<br \/>\n\u8fd9\u662f\u4e00\u4e2a\u5bf9\u6bd4 Iterator \u548c\u5f02\u6b65 iterator \u4e4b\u95f4\u5dee\u5f02\u7684\u8868\u683c\uff1a<\/li>\n<\/ol>\n<table>\n<thead>\n<tr>\n<th><\/th>\n<th>Iterator<\/th>\n<th>\u5f02\u6b65 iterator<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>\u63d0\u4f9b iterator \u7684\u5bf9\u8c61\u65b9\u6cd5<\/td>\n<td><code>Symbol.iterator<\/code><\/td>\n<td><code>Symbol.asyncIterator<\/code><\/td>\n<\/tr>\n<tr>\n<td><code>next()<\/code>\u00a0\u8fd4\u56de\u7684\u503c\u662f<\/td>\n<td>\u4efb\u610f\u503c<\/td>\n<td><code>Promise<\/code><\/td>\n<\/tr>\n<tr>\n<td>\u8981\u8fdb\u884c\u5faa\u73af\uff0c\u4f7f\u7528<\/td>\n<td><code>for..of<\/code><\/td>\n<td><code>for await..of<\/code><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<blockquote>\n<p>Spread \u8bed\u6cd5\u00a0<code>...<\/code>\u00a0\u65e0\u6cd5\u5f02\u6b65\u5de5\u4f5c<br \/>\n\u9700\u8981\u5e38\u89c4\u7684\u540c\u6b65 iterator \u7684\u529f\u80fd\uff0c\u65e0\u6cd5\u4e0e\u5f02\u6b65 iterator \u4e00\u8d77\u4f7f\u7528\u3002<br \/>\n\u4f8b\u5982\uff0cspread \u8bed\u6cd5\u65e0\u6cd5\u5de5\u4f5c\uff1a<\/p>\n<\/blockquote>\n<pre><code class=\"language-js\">alert( [...range] ); \/\/ Error, no Symbol.iterator\n<\/code><\/pre>\n<blockquote>\n<p>\u8fd9\u5f88\u6b63\u5e38\uff0c\u56e0\u4e3a\u5b83\u671f\u671b\u627e\u5230\u00a0<code>Symbol.iterator<\/code>\uff0c\u800c\u4e0d\u662f\u00a0<code>Symbol.asyncIterator<\/code>\u3002<br \/>\n<code>for..of<\/code>\u00a0\u7684\u60c5\u51b5\u548c\u8fd9\u4e2a\u4e00\u6837\uff1a\u6ca1\u6709\u00a0<code>await<\/code>\u00a0\u5173\u952e\u5b57\u65f6\uff0c\u5219\u671f\u671b\u627e\u5230\u7684\u662f\u00a0<code>Symbol.iterator<\/code>\u3002<\/p>\n<\/blockquote>\n<h2>\u56de\u987e generator<\/h2>\n<p>\u73b0\u5728\uff0c\u8ba9\u6211\u4eec\u56de\u987e\u4e00\u4e0b generator\uff0c\u5b83\u4f7f\u6211\u4eec\u80fd\u591f\u5199\u51fa\u66f4\u77ed\u7684\u8fed\u4ee3\u4ee3\u7801\u3002\u5728\u5927\u591a\u6570\u65f6\u5019\uff0c\u5f53\u6211\u4eec\u60f3\u8981\u521b\u5efa\u4e00\u4e2a\u53ef\u8fed\u4ee3\u5bf9\u8c61\u65f6\uff0c\u6211\u4eec\u4f1a\u4f7f\u7528 generator\u3002<br \/>\n\u7b80\u5355\u8d77\u89c1\uff0c\u8fd9\u91cc\u7701\u7565\u4e86\u4e00\u4e9b\u89e3\u91ca\uff0c\u5373 generator \u662f\u201c\u751f\u6210\uff08yield\uff09\u503c\u7684\u51fd\u6570\u201d\u3002\u5173\u4e8e\u6b64\u7684\u8be6\u7ec6\u8bf4\u660e\u8bf7\u89c1\u00a0<a href=\"https:\/\/zh.javascript.info\/generators\">generator<\/a>\u00a0\u4e00\u7ae0\u3002<br \/>\nGenerator \u662f\u6807\u6709\u00a0<code>function*<\/code>\uff08\u6ce8\u610f\u661f\u53f7\uff09\u7684\u51fd\u6570\uff0c\u5b83\u4f7f\u7528\u00a0<code>yield<\/code>\u00a0\u6765\u751f\u6210\u503c\uff0c\u5e76\u4e14\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u00a0<code>for..of<\/code>\u00a0\u5faa\u73af\u6765\u904d\u5386\u5b83\u4eec\u3002<br \/>\n\u4e0b\u9762\u8fd9\u4f8b\u5b50\u751f\u6210\u4e86\u4ece\u00a0<code>start<\/code>\u00a0\u5230\u00a0<code>end<\/code>\u00a0\u7684\u4e00\u7cfb\u5217\u503c\uff1a<\/p>\n<pre><code class=\"language-js\">function* generateSequence(start, end) {\n  for (let i = start; i &lt;= end; i++) {\n    yield i;\n  }\n}\n\nfor(let value of generateSequence(1, 5)) {\n  alert(value); \/\/ 1\uff0c\u7136\u540e 2\uff0c\u7136\u540e 3\uff0c\u7136\u540e 4\uff0c\u7136\u540e 5\n}\n<\/code><\/pre>\n<p>\u6b63\u5982\u6211\u4eec\u6240\u77e5\u9053\u7684\uff0c\u8981\u4f7f\u4e00\u4e2a\u5bf9\u8c61\u53ef\u8fed\u4ee3\uff0c\u6211\u4eec\u9700\u8981\u7ed9\u5b83\u6dfb\u52a0\u00a0<code>Symbol.iterator<\/code>\u3002<\/p>\n<pre><code class=\"language-js\">let range = {\n  from: 1,\n  to: 5,\n  [Symbol.iterator]() {\n    return &lt;\u5e26\u6709 next \u65b9\u6cd5\u7684\u5bf9\u8c61\uff0c\u4ee5\u4f7f\u5bf9\u8c61 range \u53ef\u8fed\u4ee3&gt;\n  }\n}\n<\/code><\/pre>\n<p>\u5bf9\u4e8e\u00a0<code>Symbol.iterator<\/code>\u00a0\u6765\u8bf4\uff0c\u4e00\u4e2a\u901a\u5e38\u7684\u505a\u6cd5\u662f\u8fd4\u56de\u4e00\u4e2a generator\uff0c\u8fd9\u6837\u53ef\u4ee5\u4f7f\u4ee3\u7801\u66f4\u77ed\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n<pre><code class=\"language-js\">let range = {\n  from: 1,\n  to: 5,\n\n  *[Symbol.iterator]() { \/\/ [Symbol.iterator]: function*() \u7684\u4e00\u79cd\u7b80\u5199\n    for(let value = this.from; value &lt;= this.to; value++) {\n      yield value;\n    }\n  }\n};\n\nfor(let value of range) {\n  alert(value); \/\/ 1\uff0c\u7136\u540e 2\uff0c\u7136\u540e 3\uff0c\u7136\u540e 4\uff0c\u7136\u540e 5\n}\n<\/code><\/pre>\n<p>\u5728\u5e38\u89c4\u7684 generator \u4e2d\uff0c\u6211\u4eec\u65e0\u6cd5\u4f7f\u7528\u00a0<code>await<\/code>\u3002\u6240\u6709\u7684\u503c\u90fd\u5fc5\u987b\u6309\u7167\u00a0<code>for..of<\/code>\u00a0\u6784\u9020\u7684\u8981\u6c42\u540c\u6b65\u5730\u51fa\u73b0\u3002<br \/>\n\u5982\u679c\u6211\u4eec\u60f3\u8981\u5f02\u6b65\u5730\u751f\u6210\u503c\u8be5\u600e\u4e48\u529e\uff1f\u4f8b\u5982\uff0c\u5bf9\u4e8e\u6765\u81ea\u7f51\u7edc\u8bf7\u6c42\u7684\u503c\u3002<br \/>\n\u8ba9\u6211\u4eec\u518d\u56de\u5230\u5f02\u6b65 generator\uff0c\u6765\u4f7f\u8fd9\u4e2a\u9700\u6c42\u6210\u4e3a\u53ef\u80fd\u3002<\/p>\n<h2>\u5f02\u6b65 generator\uff08finally\uff09<\/h2>\n<p>\u5bf9\u4e8e\u5927\u591a\u6570\u7684\u5b9e\u9645\u5e94\u7528\u7a0b\u5e8f\uff0c\u5f53\u6211\u4eec\u60f3\u521b\u5efa\u4e00\u4e2a\u5f02\u6b65\u751f\u6210\u4e00\u7cfb\u5217\u503c\u7684\u5bf9\u8c61\u65f6\uff0c\u6211\u4eec\u90fd\u53ef\u4ee5\u4f7f\u7528\u5f02\u6b65 generator\u3002<br \/>\n\u8bed\u6cd5\u5f88\u7b80\u5355\uff1a\u5728\u00a0<code>function*<\/code>\u00a0\u524d\u9762\u52a0\u4e0a\u00a0<code>async<\/code>\u3002\u8fd9\u5373\u53ef\u4f7f generator \u53d8\u4e3a\u5f02\u6b65\u7684\u3002<br \/>\n\u7136\u540e\u4f7f\u7528\u00a0<code>for await (...)<\/code>\u00a0\u6765\u904d\u5386\u5b83\uff0c\u50cf\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js\">async function* generateSequence(start, end) {\n\n  for (let i = start; i &lt;= end; i++) {\n\n    \/\/ \u54c7\uff0c\u53ef\u4ee5\u4f7f\u7528 await \u4e86\uff01\n    await new Promise(resolve =&gt; setTimeout(resolve, 1000));\n\n    yield i;\n  }\n\n}\n\n(async () =&gt; {\n\n  let generator = generateSequence(1, 5);\n  for await (let value of generator) {\n    alert(value); \/\/ 1\uff0c\u7136\u540e 2\uff0c\u7136\u540e 3\uff0c\u7136\u540e 4\uff0c\u7136\u540e 5\uff08\u5728\u6bcf\u4e2a alert \u4e4b\u95f4\u6709\u5ef6\u8fdf\uff09\n  }\n\n})();\n<\/code><\/pre>\n<p>\u56e0\u4e3a\u6b64 generator \u662f\u5f02\u6b65\u7684\uff0c\u6240\u4ee5\u6211\u4eec\u53ef\u4ee5\u5728\u5176\u5185\u90e8\u4f7f\u7528\u00a0<code>await<\/code>\uff0c\u4f9d\u8d56\u4e8e\u00a0<code>promise<\/code>\uff0c\u6267\u884c\u7f51\u7edc\u8bf7\u6c42\u7b49\u4efb\u52a1\u3002<\/p>\n<blockquote>\n<p>\u5f15\u64ce\u76d6\u4e0b\u7684\u5dee\u5f02<br \/>\n\u5982\u679c\u4f60\u8fd8\u8bb0\u5f97\u6211\u4eec\u5728\u524d\u9762\u7ae0\u8282\u4e2d\u6240\u8bb2\u7684\u5173\u4e8e generator \u7684\u7ec6\u8282\u77e5\u8bc6\uff0c\u90a3\u4f60\u5e94\u8be5\u77e5\u9053\uff0c\u4ece\u6280\u672f\u4e0a\u8bb2\uff0c\u5f02\u6b65 generator \u548c\u5e38\u89c4\u7684 generator \u5728\u5185\u90e8\u662f\u6709\u533a\u522b\u7684\u3002<br \/>\n\u5bf9\u4e8e\u5f02\u6b65 generator\uff0c<code>generator.next()<\/code>\u00a0\u65b9\u6cd5\u662f\u5f02\u6b65\u7684\uff0c\u5b83\u8fd4\u56de promise\u3002<br \/>\n\u5728\u4e00\u4e2a\u5e38\u89c4\u7684 generator \u4e2d\uff0c\u6211\u4eec\u4f7f\u7528\u00a0<code>result = generator.next()<\/code>\u00a0\u6765\u83b7\u5f97\u503c\u3002\u4f46\u5728\u4e00\u4e2a\u5f02\u6b65 generator \u4e2d\uff0c\u6211\u4eec\u5e94\u8be5\u6dfb\u52a0\u00a0<code>await<\/code>\u00a0\u5173\u952e\u5b57\uff0c\u50cf\u8fd9\u6837\uff1a<\/p>\n<\/blockquote>\n<pre><code class=\"language-js\">result = await generator.next(); \/\/ result = {value: ..., done: true\/false}\n<\/code><\/pre>\n<blockquote>\n<p>\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48\u5f02\u6b65 generator \u53ef\u4ee5\u4e0e\u00a0<code>for await...of<\/code>\u00a0\u4e00\u8d77\u5de5\u4f5c\u3002<\/p>\n<\/blockquote>\n<h3>\u5f02\u6b65\u7684\u53ef\u8fed\u4ee3\u5bf9\u8c61 range<\/h3>\n<p>\u5e38\u89c4\u7684 generator \u53ef\u7528\u4f5c\u00a0<code>Symbol.iterator<\/code>\u00a0\u4ee5\u4f7f\u8fed\u4ee3\u4ee3\u7801\u66f4\u77ed\u3002<br \/>\n\u4e0e\u4e4b\u7c7b\u4f3c\uff0c\u5f02\u6b65 generator \u53ef\u7528\u4f5c\u00a0<code>Symbol.asyncIterator<\/code>\u00a0\u6765\u5b9e\u73b0\u5f02\u6b65\u8fed\u4ee3\u3002<br \/>\n\u4f8b\u5982\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u5c06\u540c\u6b65\u7684\u00a0<code>Symbol.iterator<\/code>\u00a0\u66ff\u6362\u4e3a\u5f02\u6b65\u7684\u00a0<code>Symbol.asyncIterator<\/code>\uff0c\u6765\u4f7f\u5bf9\u8c61\u00a0<code>range<\/code>\u00a0\u5f02\u6b65\u5730\u751f\u6210\u503c\uff0c\u6bcf\u79d2\u751f\u6210\u4e00\u4e2a\uff1a<\/p>\n<pre><code class=\"language-js\">let range = {\n  from: 1,\n  to: 5,\n\n  \/\/ \u8fd9\u4e00\u884c\u7b49\u4ef7\u4e8e [Symbol.asyncIterator]: async function*() {\n  async *[Symbol.asyncIterator]() {\n    for(let value = this.from; value &lt;= this.to; value++) {\n\n      \/\/ \u5728 value \u4e4b\u95f4\u6682\u505c\u4e00\u4f1a\u513f\uff0c\u7b49\u5f85\u4e00\u4e9b\u4e1c\u897f\n      await new Promise(resolve =&gt; setTimeout(resolve, 1000));\n\n      yield value;\n    }\n  }\n};\n\n(async () =&gt; {\n\n  for await (let value of range) {\n    alert(value); \/\/ 1\uff0c\u7136\u540e 2\uff0c\u7136\u540e 3\uff0c\u7136\u540e 4\uff0c\u7136\u540e 5\n  }\n\n})();\n<\/code><\/pre>\n<p>\u73b0\u5728\uff0cvalue \u4e4b\u95f4\u7684\u5ef6\u8fdf\u4e3a 1 \u79d2\u3002<\/p>\n<blockquote>\n<p>\u8bf7\u6ce8\u610f\uff1a<br \/>\n\u4ece\u6280\u672f\u4e0a\u8bb2\uff0c\u6211\u4eec\u53ef\u4ee5\u628a\u00a0<code>Symbol.iterator<\/code>\u00a0\u548c\u00a0<code>Symbol.asyncIterator<\/code>\u00a0\u90fd\u6dfb\u52a0\u5230\u5bf9\u8c61\u4e2d\uff0c\u56e0\u6b64\u5b83\u65e2\u53ef\u4ee5\u662f\u540c\u6b65\u7684\uff08<code>for..of<\/code>\uff09\u4e5f\u53ef\u4ee5\u662f\u5f02\u6b65\u7684\uff08<code>for await..of<\/code>\uff09\u53ef\u8fed\u4ee3\u5bf9\u8c61\u3002<br \/>\n\u4f46\u662f\u5b9e\u9645\u4e0a\uff0c\u8fd9\u5c06\u662f\u4e00\u4ef6\u5f88\u5947\u602a\u7684\u4e8b\u60c5\u3002<\/p>\n<\/blockquote>\n<h2>\u5b9e\u9645\u7684\u4f8b\u5b50\uff1a\u5206\u9875\u7684\u6570\u636e<\/h2>\n<p>\u5230\u76ee\u524d\u4e3a\u6b62\uff0c\u6211\u4eec\u5df2\u7ecf\u4e86\u89e3\u4e86\u4e00\u4e9b\u57fa\u672c\u793a\u4f8b\uff0c\u4ee5\u52a0\u6df1\u7406\u89e3\u3002\u73b0\u5728\uff0c\u6211\u4eec\u6765\u770b\u4e00\u4e2a\u5b9e\u9645\u7684\u7528\u4f8b\u3002<br \/>\n\u76ee\u524d\uff0c\u6709\u5f88\u591a\u5728\u7ebf\u670d\u52a1\u90fd\u662f\u53d1\u9001\u7684\u5206\u9875\u7684\u6570\u636e\uff08paginated data\uff09\u3002\u4f8b\u5982\uff0c\u5f53\u6211\u4eec\u9700\u8981\u4e00\u4e2a\u7528\u6237\u5217\u8868\u65f6\uff0c\u4e00\u4e2a\u8bf7\u6c42\u53ea\u8fd4\u56de\u4e00\u4e2a\u9884\u8bbe\u6570\u91cf\u7684\u7528\u6237\uff08\u4f8b\u5982 100 \u4e2a\u7528\u6237\uff09\u2014\u2014 \u201c\u4e00\u9875\u201d\uff0c\u5e76\u63d0\u4f9b\u4e86\u6307\u5411\u4e0b\u4e00\u9875\u7684 URL\u3002<br \/>\n\u8fd9\u79cd\u6a21\u5f0f\u975e\u5e38\u5e38\u89c1\u3002\u4e0d\u4ec5\u53ef\u7528\u4e8e\u83b7\u53d6\u7528\u6237\u5217\u8868\uff0c\u8fd9\u79cd\u6a21\u5f0f\u8fd8\u53ef\u4ee5\u7528\u4e8e\u4efb\u610f\u4e1c\u897f\u3002<br \/>\n\u4f8b\u5982\uff0cGitHub \u5141\u8bb8\u4f7f\u7528\u76f8\u540c\u7684\u5206\u9875\u63d0\u4ea4\uff08paginated fashion\uff09\u7684\u65b9\u5f0f\u627e\u56de commit\uff1a<\/p>\n<ul>\n<li>\u6211\u4eec\u5e94\u8be5\u4ee5\u00a0<code>https:\/\/api.github.com\/repos\/&lt;repo&gt;\/commits<\/code>\u00a0\u683c\u5f0f\u521b\u5efa\u8fdb\u884c\u00a0<code>fetch<\/code>\u00a0\u7684\u7f51\u7edc\u8bf7\u6c42\u3002<\/li>\n<li>\u5b83\u8fd4\u56de\u4e00\u4e2a\u5305\u542b 30 \u6761 commit \u7684 JSON\uff0c\u5e76\u5728\u8fd4\u56de\u7684\u00a0<code>Link<\/code>\u00a0header \u4e2d\u63d0\u4f9b\u4e86\u6307\u5411\u4e0b\u4e00\u9875\u7684\u94fe\u63a5\u3002<\/li>\n<li>\u7136\u540e\u6211\u4eec\u53ef\u4ee5\u5c06\u8be5\u94fe\u63a5\u7528\u4e8e\u4e0b\u4e00\u4e2a\u8bf7\u6c42\uff0c\u4ee5\u83b7\u53d6\u66f4\u591a commit\uff0c\u4ee5\u6b64\u7c7b\u63a8\u3002<br \/>\n\u5bf9\u4e8e\u6211\u4eec\u7684\u4ee3\u7801\uff0c\u6211\u4eec\u5e0c\u671b\u6709\u4e00\u79cd\u66f4\u7b80\u5355\u7684\u83b7\u53d6 commit \u7684\u65b9\u5f0f\u3002<br \/>\n\u8ba9\u6211\u4eec\u521b\u5efa\u4e00\u4e2a\u51fd\u6570\u00a0<code>fetchCommits(repo)<\/code>\uff0c\u7528\u6765\u5728\u4efb\u4f55\u6211\u4eec\u6709\u9700\u8981\u7684\u65f6\u5019\u53d1\u51fa\u8bf7\u6c42\uff0c\u6765\u4e3a\u6211\u4eec\u83b7\u53d6 commit\u3002\u5e76\u4e14\uff0c\u8be5\u51fd\u6570\u80fd\u591f\u5173\u6ce8\u5230\u6240\u6709\u5206\u9875\u5185\u5bb9\u3002\u5bf9\u4e8e\u6211\u4eec\u6765\u8bf4\uff0c\u5b83\u5c06\u662f\u4e00\u4e2a\u7b80\u5355\u7684\u00a0<code>for await..of<\/code>\u00a0\u5f02\u6b65\u8fed\u4ee3\u3002<br \/>\n\u56e0\u6b64\uff0c\u5176\u7528\u6cd5\u5c06\u5982\u4e0b\u6240\u793a\uff1a<\/li>\n<\/ul>\n<pre><code class=\"language-js\">for await (let commit of fetchCommits(&quot;username\/repository&quot;)) {\n  \/\/ \u5904\u7406 commit\n}\n<\/code><\/pre>\n<p>\u901a\u8fc7\u5f02\u6b65 generator\uff0c\u6211\u4eec\u53ef\u4ee5\u8f7b\u677e\u5b9e\u73b0\u4e0a\u9762\u6240\u63cf\u8ff0\u7684\u51fd\u6570\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n<pre><code class=\"language-js\">async function* fetchCommits(repo) {\n  let url = `https:\/\/api.github.com\/repos\/${repo}\/commits`;\n\n  while (url) {\n    const response = await fetch(url, { \/\/ (1)\n      headers: {'User-Agent': 'Our script'}, \/\/ github \u9700\u8981\u4efb\u610f\u7684 user-agent header\n    });\n\n    const body = await response.json(); \/\/ (2) \u54cd\u5e94\u7684\u662f JSON\uff08array of commits\uff09\n\n    \/\/ (3) \u524d\u5f80\u4e0b\u4e00\u9875\u7684 URL \u5728 header \u4e2d\uff0c\u63d0\u53d6\u5b83\n    let nextPage = response.headers.get('Link').match(\/&lt;(.*?)&gt;; rel=&quot;next&quot;\/);\n    nextPage = nextPage?.[1];\n\n    url = nextPage;\n\n    for(let commit of body) { \/\/ (4) \u4e00\u4e2a\u63a5\u4e00\u4e2a\u5730 yield commit\uff0c\u76f4\u5230\u6700\u540e\u4e00\u9875\n      yield commit;\n    }\n  }\n}\n<\/code><\/pre>\n<p>\u5173\u4e8e\u5176\u5de5\u4f5c\u539f\u7406\u7684\u8fdb\u4e00\u6b65\u89e3\u91ca\uff1a<\/p>\n<ol>\n<li>\u6211\u4eec\u4f7f\u7528\u6d4f\u89c8\u5668\u7684\u00a0<a href=\"https:\/\/zh.javascript.info\/fetch\">fetch<\/a>\u00a0\u65b9\u6cd5\u6765\u4e0b\u8f7d commit\u3002\n<ul>\n<li>\u521d\u59cb URL \u662f\u00a0<code>https:\/\/api.github.com\/repos\/&lt;repo&gt;\/commits<\/code>\uff0c\u5e76\u4e14\u4e0b\u4e00\u9875\u7684 URL \u5c06\u5728\u54cd\u5e94\u7684\u00a0<code>Link<\/code>\u00a0header \u4e2d\u3002<\/li>\n<li><code>fetch<\/code>\u00a0\u65b9\u6cd5\u5141\u8bb8\u6211\u4eec\u63d0\u4f9b\u6388\u6743\u548c\u5176\u4ed6 header\uff0c\u5982\u679c\u9700\u8981 \u2014\u2014 \u8fd9\u91cc GitHub \u9700\u8981\u7684\u662f\u00a0<code>User-Agent<\/code>\u3002<\/li>\n<\/ul>\n<\/li>\n<li>commit \u88ab\u4ee5 JSON \u7684\u683c\u5f0f\u8fd4\u56de\u3002<\/li>\n<li>\u6211\u4eec\u5e94\u8be5\u4ece\u54cd\u5e94\uff08response\uff09\u7684\u00a0<code>Link<\/code>\u00a0header \u4e2d\u83b7\u53d6\u524d\u5f80\u4e0b\u4e00\u9875\u7684 URL\u3002\u5b83\u6709\u4e00\u4e2a\u7279\u6b8a\u7684\u683c\u5f0f\uff0c\u6240\u4ee5\u6211\u4eec\u5bf9\u5b83\u4f7f\u7528\u6b63\u5219\u8868\u8fbe\u5f0f\uff08\u6211\u4eec\u5c06\u5728\u00a0<a href=\"https:\/\/zh.javascript.info\/regular-expressions\">\u6b63\u5219\u8868\u8fbe\u5f0f<\/a>\u00a0\u4e00\u7ae0\u4e2d\u5b66\u4e60\u5b83\uff09\u3002\n<ul>\n<li>\u524d\u5f80\u4e0b\u4e00\u9875\u7684 URL \u770b\u8d77\u6765\u53ef\u80fd\u5c31\u50cf\u8fd9\u6837\u00a0<code>https:\/\/api.github.com\/repositories\/93253246\/commits?page=2<\/code>\u3002\u8fd9\u662f\u7531 GitHub \u81ea\u5df1\u751f\u6210\u7684\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\u7136\u540e\uff0c\u6211\u4eec\u5c06\u63a5\u6536\u5230\u7684\u6240\u6709 commit \u4e00\u4e2a\u4e00\u4e2a\u5730 yield \u51fa\u6765\uff0c\u5f53\u6240\u6709 commit \u90fd yield \u5b8c\u6210\u65f6\uff0c\u5c06\u89e6\u53d1\u4e0b\u4e00\u4e2a\u00a0<code>while(url)<\/code>\u00a0\u8fed\u4ee3\uff0c\u5e76\u53d1\u51fa\u4e0b\u4e00\u4e2a\u8bf7\u6c42\u3002<br \/>\n\u8fd9\u662f\u4e00\u4e2a\u4f7f\u7528\u793a\u4f8b\uff08\u5728\u63a7\u5236\u53f0\u4e2d\u663e\u793a commit \u7684\u4f5c\u8005\uff09<\/li>\n<\/ol>\n<pre><code class=\"language-js\">(async () =&gt; {\n\n  let count = 0;\n\n  for await (const commit of fetchCommits('javascript-tutorial\/en.javascript.info')) {\n\n    console.log(commit.author.login);\n\n    if (++count == 100) { \/\/ \u8ba9\u6211\u4eec\u5728\u83b7\u53d6\u4e86 100 \u4e2a commit \u65f6\u505c\u6b62\n      break;\n    }\n  }\n\n})();\n\n\/\/ \u6ce8\u610f\uff1a\u5982\u679c\u4f60\u5728\u5916\u90e8\u6c99\u7bb1\u4e2d\u8fd0\u884c\u5b83\uff0c\u4f60\u9700\u8981\u628a\u4e0a\u9762\u7684 fetchCommits \u51fd\u6570\u7c98\u8d34\u5230\u8fd9\u513f\u3002\n<\/code><\/pre>\n<p>\u8fd9\u5c31\u662f\u6211\u4eec\u60f3\u8981\u7684\u3002<br \/>\n\u4ece\u5916\u90e8\u770b\u4e0d\u5230\u5206\u9875\u8bf7\u6c42\uff08paginated requests\uff09\u7684\u5185\u90e8\u673a\u5236\u3002\u5bf9\u6211\u4eec\u6765\u8bf4\uff0c\u5b83\u53ea\u662f\u4e00\u4e2a\u8fd4\u56de commit \u7684\u5f02\u6b65 generator\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>generator \u5e38\u89c4\u51fd\u6570\u53ea\u4f1a\u8fd4\u56de\u4e00\u4e2a\u5355\u4e00\u503c\uff08\u6216\u8005\u4e0d\u8fd4\u56de\u4efb\u4f55\u503c\uff09\u3002 \u800c generator \u53ef\u4ee5\u6309\u9700\u4e00\u4e2a\u63a5\u4e00 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[19],"tags":[],"class_list":["post-673","post","type-post","status-publish","format-standard","hentry","category-front-end"],"_links":{"self":[{"href":"https:\/\/levin.ink\/index.php?rest_route=\/wp\/v2\/posts\/673","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/levin.ink\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/levin.ink\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/levin.ink\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/levin.ink\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=673"}],"version-history":[{"count":1,"href":"https:\/\/levin.ink\/index.php?rest_route=\/wp\/v2\/posts\/673\/revisions"}],"predecessor-version":[{"id":674,"href":"https:\/\/levin.ink\/index.php?rest_route=\/wp\/v2\/posts\/673\/revisions\/674"}],"wp:attachment":[{"href":"https:\/\/levin.ink\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=673"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/levin.ink\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=673"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/levin.ink\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=673"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}