{"id":170169,"date":"2024-05-08T17:01:58","date_gmt":"2024-05-08T09:01:58","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/170169.html"},"modified":"2024-05-08T17:02:06","modified_gmt":"2024-05-08T09:02:06","slug":"javascript-%e7%a8%8b%e5%ba%8f%e4%b8%ad%e6%80%8e%e4%b9%88%e5%ae%9e%e7%8e%b0%e6%95%b0%e7%bb%84%e9%81%8d%e5%8e%86","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/170169.html","title":{"rendered":"JavaScript \u7a0b\u5e8f\u4e2d\u600e\u4e48\u5b9e\u73b0\u6570\u7ec4\u904d\u5386"},"content":{"rendered":"

\"JavaScript<\/p>\n

\u5728JavaScript\u7a0b\u5e8f\u4e2d\uff0c\u5b9e\u73b0\u6570\u7ec4\u904d\u5386\u7684\u4e3b\u8981\u65b9\u6cd5\u6709for<\/code>\u5faa\u73af\u3001forEach<\/code>\u65b9\u6cd5\u3001for...of<\/code>\u5faa\u73af\u3001map<\/code>\u65b9\u6cd5\u3002\u8fd9\u4e9b\u65b9\u6cd5\u5404\u6709\u7279\u70b9\uff0c\u80fd\u6ee1\u8db3\u4e0d\u540c\u573a\u666f\u4e0b\u7684\u6570\u7ec4\u904d\u5386\u9700\u6c42\u3002\u5728\u8fd9\u4e9b\u65b9\u6cd5\u4e2d\uff0cfor<\/code>\u5faa\u73af<\/strong>\u662f\u6700\u57fa\u672c\u4e5f\u662f\u6700\u7075\u6d3b\u7684\u904d\u5386\u65b9\u5f0f\uff0c\u5b83\u4e0d\u4ec5\u9002\u7528\u4e8e\u6570\u7ec4\uff0c\u8fd8\u53ef\u4ee5\u904d\u5386\u5176\u4ed6\u53ef\u8fed\u4ee3\u5bf9\u8c61\u3002for<\/code>\u5faa\u73af\u5141\u8bb8\u4f60\u81ea\u5b9a\u4e49\u904d\u5386\u7684\u8d77\u70b9\u3001\u7ec8\u70b9\u548c\u6b65\u957f\uff0c\u56e0\u6b64\u5f53\u9700\u8981\u5bf9\u904d\u5386\u8fc7\u7a0b\u8fdb\u884c\u7ec6\u7c92\u5ea6\u63a7\u5236\u65f6\uff0c\u8fd9\u79cd\u65b9\u5f0f\u975e\u5e38\u6709\u7528\u3002<\/p>\n<\/p>\n

\u4e00\u3001FOR \u5faa\u73af<\/h3>\n<\/p>\n

for<\/code>\u5faa\u73af\u662f\u5b9e\u73b0\u6570\u7ec4\u904d\u5386\u7684\u4e00\u79cd\u57fa\u672c\u65b9\u5f0f\uff0c\u5b83\u901a\u8fc7\u7d22\u5f15\u6765\u8bbf\u95ee\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\u3002<\/p>\n<\/p>\n

const array = [1, 2, 3, 4, 5];<\/p>\n
for (let i = 0; i < array.length; i++) {<\/p>\n
  console.log(array[i]);<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8fd9\u79cd\u65b9\u6cd5\u7684\u4f18\u70b9\u5728\u4e8e\u5176\u7075\u6d3b\u6027\u9ad8\uff0c\u53ef\u4ee5\u901a\u8fc7\u8c03\u6574\u7d22\u5f15\u503c\u548c\u6761\u4ef6\u5224\u65ad\uff0c\u7075\u6d3b\u5730\u63a7\u5236\u904d\u5386\u7684\u8d77\u59cb\u70b9\u548c\u7ec8\u6b62\u70b9\uff0c\u4ee5\u53ca\u904d\u5386\u7684\u65b9\u5411\uff08\u6b63\u5e8f\u6216\u5012\u5e8f\u904d\u5386\uff09\u3002\u6b64\u5916\uff0cfor<\/code>\u5faa\u73af\u4e0d\u4ec5\u9002\u7528\u4e8e\u6570\u7ec4\uff0c\u8fd8\u53ef\u4ee5\u904d\u5386\u5bf9\u8c61\u3001\u5b57\u7b26\u4e32\u7b49\u6570\u636e\u7ed3\u6784\u3002<\/p>\n<\/p>\n
\u4e8c\u3001FOREACH \u65b9\u6cd5<\/h3>\n<\/p>\n
forEach<\/code>\u65b9\u6cd5\u662fArray\u539f\u578b\u4e0a\u7684\u4e00\u4e2a\u65b9\u6cd5\uff0c\u5b83\u4e3a\u6570\u7ec4\u4e2d\u6bcf\u4e2a\u5143\u7d20\u6267\u884c\u4e00\u6b21\u63d0\u4f9b\u7684\u51fd\u6570\u3002<\/p>\n<\/p>\n
const array = ['a', 'b', 'c', 'd'];<\/p>\n
array.forEach(function(element, index) {<\/p>\n
    console.log(index + ": " + element);<\/p>\n
});<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f7f\u7528forEach<\/code>\u65b9\u6cd5\u53ef\u4ee5\u7b80\u5316\u904d\u5386\u6570\u7ec4\u7684\u4ee3\u7801\uff0c\u4f7f\u5176\u66f4\u52a0\u7b80\u6d01\u660e\u4e86\u3002\u4e0d\u8fc7\uff0c\u9700\u8981\u6ce8\u610f\u7684\u662fforEach<\/code>\u65e0\u6cd5\u5728\u56de\u8c03\u51fd\u6570\u4e2d\u4f7f\u7528break<\/code>\u6216return<\/code>\u63d0\u524d\u9000\u51fa\u5faa\u73af\u3002<\/strong><\/p>\n<\/p>\n
\u4e09\u3001FOR…OF \u5faa\u73af<\/h3>\n<\/p>\n
for...of<\/code>\u5faa\u73af\u662fES6\u5f15\u5165\u7684\u4e00\u79cd\u65b0\u7684\u904d\u5386\u65b9\u6cd5\uff0c\u5b83\u53ef\u4ee5\u904d\u5386\u6240\u6709\u53ef\u8fed\u4ee3\u7684\u5bf9\u8c61\uff0c\u5305\u62ec\u6570\u7ec4\u3001Map\u3001Set\u7b49\u3002<\/p>\n<\/p>\n
const array = [10, 20, 30, 40, 50];<\/p>\n
for (const value of array) {<\/p>\n
  console.log(value);<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
for...of<\/code>\u5faa\u73af\u7684\u4f18\u70b9\u5728\u4e8e\u5176\u7b80\u6d01\u6027\u548c\u5bf9\u65b0\u7684\u6570\u636e\u7ed3\u6784\u6709\u826f\u597d\u7684\u652f\u6301\u3002\u5b83\u76f4\u63a5\u904d\u5386\u7684\u662f\u5143\u7d20\u503c\uff0c\u800c\u4e0d\u662f\u5143\u7d20\u7684\u7d22\u5f15\uff0c\u8fd9\u4f7f\u5f97\u4ee3\u7801\u66f4\u52a0\u76f4\u89c2\u6613\u61c2\u3002<\/p>\n<\/p>\n
\u56db\u3001MAP \u65b9\u6cd5<\/h3>\n<\/p>\n
map<\/code>\u65b9\u6cd5\u521b\u5efa\u4e00\u4e2a\u65b0\u6570\u7ec4\uff0c\u5176\u7ed3\u679c\u662f\u8be5\u6570\u7ec4\u4e2d\u7684\u6bcf\u4e2a\u5143\u7d20\u662f\u8c03\u7528\u4e00\u6b21\u63d0\u4f9b\u7684\u51fd\u6570\u540e\u7684\u8fd4\u56de\u503c\u3002<\/p>\n<\/p>\n
const array = [1, 2, 3, 4, 5];<\/p>\n
const squareArray = array.map(x => x * x);<\/p>\n
console.log(squareArray);<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f7f\u7528map<\/code>\u65b9\u6cd5\u53ef\u4ee5\u975e\u5e38\u65b9\u4fbf\u5730\u5bf9\u6570\u7ec4\u4e2d\u7684\u6bcf\u4e2a\u5143\u7d20\u8fdb\u884c\u5904\u7406\uff0c\u5e76\u5c06\u5904\u7406\u7ed3\u679c\u7ec4\u6210\u4e00\u4e2a\u65b0\u7684\u6570\u7ec4\u8fd4\u56de\u3002\u8fd9\u79cd\u65b9\u6cd5\u7279\u522b\u9002\u7528\u4e8e\u9700\u8981\u5bf9\u6570\u7ec4\u8fdb\u884c\u8f6c\u6362\u7684\u573a\u666f\u3002\u6ce8\u610fmap<\/code>\u65b9\u6cd5\u5e76\u4e0d\u4f1a\u4fee\u6539\u539f\u59cb\u6570\u7ec4\u3002<\/strong><\/p>\n<\/p>\n
\u5b9e\u73b0\u6570\u7ec4\u904d\u5386\u7684\u65b9\u6cd5\u5404\u6709\u7279\u6027\uff0c\u9009\u62e9\u54ea\u79cd\u65b9\u6cd5\u53d6\u51b3\u4e8e\u5177\u4f53\u7684\u5e94\u7528\u573a\u666f\u4ee5\u53ca\u4e2a\u4eba\u7684\u7f16\u7a0b\u98ce\u683c\u3002\u4e86\u89e3\u548c\u638c\u63e1\u8fd9\u4e9b\u65b9\u6cd5\uff0c\u80fd\u591f\u8ba9\u6211\u4eec\u5728\u5904\u7406\u6570\u7ec4\u6570\u636e\u65f6\u66f4\u52a0\u5f97\u5fc3\u5e94\u624b\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
1. \u5982\u4f55\u4f7f\u7528\u5faa\u73af\u6765\u5b9e\u73b0 JavaScript \u6570\u7ec4\u7684\u904d\u5386\uff1f<\/strong><\/p>\n
\u5728 JavaScript \u7a0b\u5e8f\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u5faa\u73af\u7ed3\u6784\u6765\u904d\u5386\u6570\u7ec4\u5143\u7d20\u3002\u5e38\u89c1\u7684\u5faa\u73af\u7ed3\u6784\u6709 for \u5faa\u73af\u548c forEach \u65b9\u6cd5\u3002<\/p>\n
\u4f7f\u7528 for \u5faa\u73af\u904d\u5386\u6570\u7ec4\u7684\u65b9\u5f0f\u5982\u4e0b\uff1a<\/p>\n
let arr = [1, 2, 3, 4, 5];\nfor (let i = 0; i < arr.length; i++) {\n    console.log(arr[i]);\n}\n<\/code><\/pre>\n
\u4f7f\u7528 forEach \u65b9\u6cd5\u6765\u904d\u5386\u6570\u7ec4\u7684\u65b9\u5f0f\u5982\u4e0b\uff1a<\/p>\n
let arr = [1, 2, 3, 4, 5];\narr.forEach(function(element) {\n    console.log(element);\n});\n<\/code><\/pre>\n
2. \u53ef\u4ee5\u4f7f\u7528\u54ea\u4e9b\u9ad8\u7ea7\u7684\u904d\u5386\u65b9\u6cd5\u6765\u5904\u7406 JavaScript \u6570\u7ec4\uff1f<\/strong><\/p>\n
\u9664\u4e86\u5e38\u7528\u7684 for \u5faa\u73af\u548c forEach \u65b9\u6cd5\u5916\uff0cJavaScript \u8fd8\u63d0\u4f9b\u4e86\u5176\u4ed6\u4e00\u4e9b\u5f3a\u5927\u7684\u6570\u7ec4\u904d\u5386\u65b9\u6cd5\u3002\u5176\u4e2d\u6700\u5e38\u7528\u7684\u662f map\u3001filter\u3001reduce\u3002<\/p>\n
    \n
  • map \u65b9\u6cd5\uff1a\u5c06\u6570\u7ec4\u4e2d\u7684\u6bcf\u4e2a\u5143\u7d20\u90fd\u6267\u884c\u6307\u5b9a\u7684\u64cd\u4f5c\uff0c\u5e76\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684\u6570\u7ec4\u3002\u4f8b\u5982\uff0c\u5c06\u6570\u7ec4\u4e2d\u7684\u6bcf\u4e2a\u5143\u7d20\u90fd\u52a0\u500d\uff1a<\/li>\n<\/ul>\n
    let arr = [1, 2, 3, 4, 5];\nlet doubledArr = arr.map(function(element) {\n    return element * 2;\n});\nconsole.log(doubledArr);\n<\/code><\/pre>\n
      \n
    • filter \u65b9\u6cd5\uff1a\u6839\u636e\u6307\u5b9a\u7684\u6761\u4ef6\u8fc7\u6ee4\u51fa\u7b26\u5408\u6761\u4ef6\u7684\u6570\u7ec4\u5143\u7d20\uff0c\u5e76\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684\u6570\u7ec4\u3002\u4f8b\u5982\uff0c\u5c06\u6570\u7ec4\u4e2d\u7684\u5947\u6570\u8fc7\u6ee4\u51fa\u6765\uff1a<\/li>\n<\/ul>\n
      let arr = [1, 2, 3, 4, 5];\nlet oddArr = arr.filter(function(element) {\n    return element % 2 !== 0;\n});\nconsole.log(oddArr);\n<\/code><\/pre>\n
        \n
      • reduce \u65b9\u6cd5\uff1a\u5c06\u6570\u7ec4\u4e2d\u7684\u6240\u6709\u5143\u7d20\u6309\u7167\u6307\u5b9a\u7684\u64cd\u4f5c\u8fdb\u884c\u7d2f\u79ef\uff0c\u5e76\u8fd4\u56de\u7d2f\u79ef\u7ed3\u679c\u3002\u4f8b\u5982\uff0c\u8ba1\u7b97\u6570\u7ec4\u4e2d\u6240\u6709\u5143\u7d20\u7684\u548c\uff1a<\/li>\n<\/ul>\n
        let arr = [1, 2, 3, 4, 5];\nlet sum = arr.reduce(function(acc, curr) {\n    return acc + curr;\n}, 0);\nconsole.log(sum);\n<\/code><\/pre>\n
        3. \u5982\u4f55\u4f7f\u7528\u9012\u5f52\u7684\u65b9\u5f0f\u6765\u904d\u5386 JavaScript \u6570\u7ec4\uff1f<\/strong><\/p>\n
        \u9012\u5f52\u662f\u4e00\u79cd\u901a\u8fc7\u51fd\u6570\u81ea\u8eab\u8c03\u7528\u6765\u89e3\u51b3\u95ee\u9898\u7684\u65b9\u6cd5\u3002\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u9012\u5f52\u7684\u65b9\u5f0f\u6765\u904d\u5386 JavaScript \u6570\u7ec4\u3002<\/p>\n
        \u901a\u8fc7\u9012\u5f52\u904d\u5386\u6570\u7ec4\u7684\u65b9\u5f0f\u5982\u4e0b\uff1a<\/p>\n
        function traverseArray(arr, index) {\n    if (index == arr.length) {\n        return;  \/\/ \u7ed3\u675f\u9012\u5f52\n    }\n  \n    console.log(arr[index]);\n    traverseArray(arr, index + 1);\n}\n\nlet arr = [1, 2, 3, 4, 5];\ntraverseArray(arr, 0);\n<\/code><\/pre>\n
        \u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u6211\u4eec\u5b9a\u4e49\u4e86\u4e00\u4e2a\u540d\u4e3a traverseArray<\/code> \u7684\u51fd\u6570\uff0c\u5b83\u63a5\u53d7\u4e24\u4e2a\u53c2\u6570\uff0c\u4e00\u4e2a\u662f\u8981\u904d\u5386\u7684\u6570\u7ec4 arr<\/code>\uff0c\u53e6\u4e00\u4e2a\u662f\u5f53\u524d\u8981\u904d\u5386\u7684\u5143\u7d20\u7684\u7d22\u5f15 index<\/code>\u3002\u51fd\u6570\u4e2d\u9996\u5148\u5224\u65ad\u7d22\u5f15\u662f\u5426\u7b49\u4e8e\u6570\u7ec4\u7684\u957f\u5ea6\uff0c\u5982\u679c\u662f\uff0c\u5219\u9012\u5f52\u7ed3\u675f\uff1b\u5426\u5219\uff0c\u6253\u5370\u5f53\u524d\u5143\u7d20\u5e76\u8c03\u7528\u81ea\u8eab\u6765\u904d\u5386\u4e0b\u4e00\u4e2a\u5143\u7d20\u3002\u6700\u540e\uff0c\u6211\u4eec\u8c03\u7528 traverseArray<\/code> \u51fd\u6570\u6765\u5f00\u59cb\u904d\u5386\u6570\u7ec4\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"\u5728JavaScript\u7a0b\u5e8f\u4e2d\uff0c\u5b9e\u73b0\u6570\u7ec4\u904d\u5386\u7684\u4e3b\u8981\u65b9\u6cd5\u6709for\u5faa\u73af\u3001forEach\u65b9\u6cd5\u3001for…of\u5faa\u73af\u3001m […]","protected":false},"author":3,"featured_media":170183,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/170169"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=170169"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/170169\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/170183"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=170169"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=170169"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=170169"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}