{"id":125,"date":"2018-10-06T01:33:36","date_gmt":"2018-10-05T17:33:36","guid":{"rendered":"https:\/\/wp.winter-weng.cc\/work\/?p=125"},"modified":"2018-10-06T01:33:36","modified_gmt":"2018-10-05T17:33:36","slug":"js-%e5%b8%b8%e7%94%a8%e7%9a%84-array-method","status":"publish","type":"post","link":"https:\/\/wp.winter-weng.cc\/work\/?p=125","title":{"rendered":"[JS] \u5e38\u7528\u7684 Array Method"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_75 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"\u986f\u793a\/\u96b1\u85cf\u5167\u5bb9\u76ee\u9304\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=125\/#1_Arrayprototypefilter\" >1. Array.prototype.filter()<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=125\/#2_Arrayprototypemap\" >2. Array.prototype.map()<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=125\/#3_Arrayprototypereduce\" >3. Array.prototype.reduce()<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=125\/#4_Arrayprototypesort\" >4. Array.prototype.sort()<\/a><\/li><\/ul><\/nav><\/div>\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1_Arrayprototypefilter\"><\/span>1. Array.prototype.filter()<br \/><span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<p>\u900f\u904e\u50b3\u5165\u7684 callback \u51fd\u5f0f\u4f5c\u6aa2\u9a57\uff0c\u56de\u50b3\u503c\u70ba\u00a0<code>true<\/code>\u00a0\u6642\u5c07\u7576\u524d\u7684\u5143\u7d20\u4fdd\u7559\u81f3<strong>\u65b0\u9663\u5217<\/strong>\u4e2d\u3002<\/p>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"js\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">var newArray = arr.filter(callback[, thisArg])<\/pre>\n\n\n<p>callback \u5305\u542b\u4e09\u500b\u53c3\u6578\uff1a<br \/>\u30001. currentValue\uff1a\u76ee\u524d\u8fed\u4ee3\u4e2d\u7684\u5143\u7d20<br \/>\u30002. currentIndex (optional)\uff1a\u76ee\u524d\u8fed\u4ee3\u4e2d\u7684\u7d22\u5f15\u503c<br \/>\u30003. array\u00a0(optional)\uff1a\u547c\u53eb filter() \u7684\u9663\u5217<\/p>\n\n\n<p>thisArg (optional) \u9810\u8a2d\u70ba undefined\uff0c\u82e5\u6709\u7d66\u5247\u6703\u88ab\u4f5c\u70ba callback \u7684 this \u503c\u3002<\/p>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"js\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">var rawData= [12, 5, 8, 130, 44];\nfunction isBiggerThanTen(value) {\n  return value &gt;= 10;\n}\nvar newArray = rawData.filter(isBiggerThanTen);\nconsole.log(newArray);\n\/\/ expected output: [12, 130, 44]<\/pre>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"js\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ ES6\nconst rawData= [12, 5, 8, 130, 44];\nconst newArray = rawData.filter(el =&gt; el &gt;= 10);<\/pre>\n\n\n<hr class=\"wp-block-separator\" \/>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2_Arrayprototypemap\"><\/span>2. Array.prototype.map()<br \/><span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<p>\u900f\u904e\u50b3\u5165\u7684 callback \u51fd\u5f0f\u4f5c\u904b\u7b97\uff0c\u5c07\u904b\u7b97\u7d50\u679c\u5132\u5b58\u5728<strong>\u65b0\u9663\u5217<\/strong>\u4e2d\u3002<\/p>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"js\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">var newArray = arr.map(callback[, thisArg]);<\/pre>\n\n\n<p>\u53c3\u6578\u8207 filter \u65b9\u6cd5\u96f7\u540c\u3002<\/p>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"js\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">const rawData= [12, 5, 8, 130, 44];\nconst newArray = rawData.map(el =&gt; el * 2);\nconsole.log(newArray);\n\/\/ expected output: [24, 10, 16, 260, 88]<\/pre>\n\n\n<hr class=\"wp-block-separator\" \/>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3_Arrayprototypereduce\"><\/span>3. Array.prototype.reduce()<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<p>\u5c07\u9663\u5217\u548c\u7d2f\u52a0\u5668\u50b3\u5165 callback \u505a\u8655\u7406\uff0c\u6700\u5f8c\u56de\u50b3\u55ae\u4e00\u503c\u3002<\/p>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"js\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">arr.reduce(callback[, initialValue]);<\/pre>\n\n\n<p>callback \u5305\u542b\u56db\u500b\u53c3\u6578\uff1a<br \/>\u30001. accumulator\uff1a\u7d2f\u52a0\u5668<br \/>\u30002. currentValue\uff1a\u76ee\u524d\u8fed\u4ee3\u4e2d\u7684\u5143\u7d20<br \/>\u30003. currentIndex (optional) \uff1a\u76ee\u524d\u8fed\u4ee3\u4e2d\u7684\u7d22\u5f15\u503c<br \/>\u30004. array\u00a0(optional)\uff1a\u547c\u53eb reduce() \u7684\u9663\u5217<\/p>\n\n\n<p>initialValue (optional)\uff0c\u7b2c\u4e00\u6b21\u547c\u53eb\u6642\u7d2f\u52a0\u5668\u7684\u521d\u59cb\u503c\uff0c\u82e5\u7121\u5247\u9810\u8a2d\u70ba\u9663\u5217\u7b2c\u4e00\u500b\u5143\u7d20\u3002<\/p>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">const rawData = [1, 2, 3, 4];\nconst reducer = (accumulator, currentValue) =&gt; accumulator + currentValue;\nconsole.log(rawData.reduce(reducer));\n\/\/ expected output: 10 (1 + 2 + 3 + 4)\nconsole.log(rawData.reduce(reducer, 5));\n\/\/ expected output: 15 (5 + 1 + 2 + 3 + 4)<\/pre>\n\n\n<hr class=\"wp-block-separator\" \/>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"4_Arrayprototypesort\"><\/span>4. Array.prototype.sort()<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<p>\u5c07\u9663\u5217\u6392\u5e8f\u5f8c\u56de\u50b3\uff0c\u9810\u8a2d\u6392\u5e8f\u662f\u6839\u64da Unicode \u7de8\u78bc\u4f4d\u7f6e\u800c\u5b9a\u3002\u53ef\u4ee5\u7d66\u5b9a\u4e00\u500b\u6bd4\u8f03\u7684\u51fd\u5f0f\uff0c\u4f86\u5b9a\u7fa9\u6392\u5e8f\u65b9\u5f0f\u3002<\/p>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"js\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">arr.Sort(compareFunction);<\/pre>\n\n\n<p>\u82e5\u6709\u7d66\u5b9a compareFunction\uff0c\u4e14\u00a0<code>a<\/code>\u00a0\u548c\u00a0<code>b<\/code>\u70ba\u88ab\u6bd4\u8f03\u4e4b\u5169\u5143\u7d20\uff0c\u5247\uff1a<\/p>\n\n\n<ul class=\"wp-block-list\"><li>\u82e5\u00a0<code>compareFunction(a, b)<\/code>\u00a0\u7684\u56de\u50b3\u503c\u5c0f\u65bc 0\uff0c\u5247\u6703\u628a\u00a0<code>a<\/code>\u00a0\u6392\u5728\u00a0<code>b<\/code>\u00a0\u524d\u9762<\/li><li>\u82e5\u00a0<code>compareFunction(a, b)<\/code>\u00a0\u7684\u56de\u50b3\u503c\u5927\u65bc 0\uff0c\u5247\u6703\u628a\u00a0<code>b<\/code>\u00a0\u6392\u5728\u00a0<code>a<\/code>\u00a0\u524d\u9762<\/li><li>\u82e5\u00a0<code>compareFunction(a, b)<\/code>\u00a0\u56de\u50b3 0\uff0c\u5247\u00a0<code>a<\/code>\u00a0\u8207\u00a0<code>b<\/code>\u00a0\u7686\u4e0d\u6703\u6539\u8b8a\u5f7c\u6b64\u7684\u9806\u5e8f\uff0c\u4f46\u6703\u8207\u5176\u4ed6\u5168\u90e8\u7684\u5143\u7d20\u6bd4\u8f03\u4f86\u6392\u5e8f\u3002\u5099\u8a3b\uff1aECMAscript \u6a19\u6e96\u4e26\u4e0d\u4fdd\u8b49\u9019\u500b\u884c\u70ba\uff0c\u56e0\u6b64\u4e0d\u662f\u6240\u6709\u700f\u89bd\u5668\uff08\u5982 Mozilla \u7248\u672c\u5728 2003 \u4ee5\u524d\uff09\u90fd\u9075\u5b88\u6b64\u884c\u70ba<br \/><\/li><li><code>compareFunction(a, b)<\/code>\u00a0\u5728\u7d66\u4e88\u4e00\u7d44\u7279\u5b9a\u5143\u7d20 a \u53ca b \u70ba\u6b64\u51fd\u6578\u4e4b\u5169\u5f15\u6578\u6642\u5fc5\u9808\u7e3d\u662f\u56de\u50b3\u76f8\u540c\u7684\u503c\u3002\u82e5\u56de\u50b3\u503c\u4e0d\u4e00\u81f4\uff0c\u6392\u5e8f\u9806\u5e8f\u5247\u70ba undefined<\/li><\/ul>\n\n\n<p>\u6bd4\u8f03\u6578\u5b57\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528\u51fd\u5f0f\u904b\u7b97\u5f0f\uff1a<\/p>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"js\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">const rawData = [1, 2, 11];\nconsole.log(rawData.sort());\n\/\/ expected output: [1, 11, 2] (sort by Unicode)\nconsole.log(rawData.sort((a,b) =&gt; a-b));\n\/\/ expected output: [1, 2, 11]<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>1. Array.prototype.filter&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"pgc_sgb_lightbox_settings":"","footnotes":""},"categories":[4],"tags":[21],"class_list":["post-125","post","type-post","status-publish","format-standard","hentry","category-javascript","tag-javascript"],"_links":{"self":[{"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=\/wp\/v2\/posts\/125","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=125"}],"version-history":[{"count":0,"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=\/wp\/v2\/posts\/125\/revisions"}],"wp:attachment":[{"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=125"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=125"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=125"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}