{"id":10102,"date":"2025-12-05T15:26:52","date_gmt":"2025-12-05T06:26:52","guid":{"rendered":"https:\/\/techmania.jp\/blog\/?p=10102"},"modified":"2025-12-05T15:26:54","modified_gmt":"2025-12-05T06:26:54","slug":"javascript-reduce","status":"publish","type":"post","link":"https:\/\/techmania.jp\/blog\/javascript-reduce\/","title":{"rendered":"\u3010JavaScript\u5165\u9580\u3011reduce\u30e1\u30bd\u30c3\u30c9\u3067\u914d\u5217\u3092\u4e00\u3064\u306e\u5024\u306b\u7e2e\u5c0f\u3059\u308b"},"content":{"rendered":"\n<p>JavaScript\u306e\u914d\u5217\u306b\u306f\u3001\u5168\u3066\u306e\u8981\u7d20\u3092\uff11\u3064\u306b\u307e\u3068\u3081\u305f\u3044\u5834\u5408\u306b\u4fbf\u5229\u306a \u300creduce\u300d \u3068\u3044\u3046\u30e1\u30bd\u30c3\u30c9\u304c\u65e2\u5b58\u3067\u7528\u610f\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u4eca\u56de\u306f\u3001reduce\u30e1\u30bd\u30c3\u30c9\u306e\u8a73\u3057\u3044\u4f7f\u3044\u65b9\u306b\u3064\u3044\u3066\u89e3\u8aac\u3092\u3057\u3066\u3044\u304d\u305f\u3044\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n\n\n\n<h2 id=\"outline__1\" class=\"wp-block-heading\">JavaScript\u306ereduce\u30e1\u30bd\u30c3\u30c9\u3068\u306f\uff1f<\/h2>\n\n\n\n<p>reduce\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u914d\u5217\u5185\u306e\u8981\u7d20\u30921\u3064\u306e\u5024\u3068\u3057\u3066\u307e\u3068\u3081\u305f\u3044\u5834\u5408\u306b\u6d3b\u7528\u3067\u304d\u308b\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002<br>\u914d\u5217\u5185\u306e\u96a3\u308a\u5408\u3046\u8981\u7d20\u306b\u5bfe\u3057\u3066\u95a2\u6570\u3092\u5b9f\u884c\u3059\u308b\u51e6\u7406\u3092\u7e70\u308a\u8fd4\u3057\u3001\u6700\u5f8c\u306e\u30eb\u30fc\u30d7\u3067\u5b9f\u884c\u3057\u305f\u6f14\u7b97\u7d50\u679c\u3092\u5358\u4e00\u306e\u5024\u3068\u3057\u3066\u53d6\u5f97\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u4f8b\u3048\u3070\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u3001\u5404\u8981\u7d20\u306b\u6570\u5024\u578b\u306e\u5024\u304c\u683c\u7d0d\u3055\u308c\u3066\u3044\u308b\u914d\u5217\u304c\u3042\u308b\u3068\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-js\" data-lang=\"JavaScript\"><code>const sampleArray = [1, 2, 3, 4, 5];<\/code><\/pre><\/div>\n\n\n\n<p>\u300c\u3053\u308c\u3089\u306e\u8981\u7d20\u3092\u5168\u3066\u5408\u7b97\u3057\u305f\u6570\u5024\u3092\u53d6\u5f97\u3057\u305f\u3044\u300d \u3068\u3044\u3063\u305f\u5834\u5408\u306b\u4f7f\u7528\u3067\u304d\u308b\u306e\u304c\u3001reduce\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002<\/p>\n\n\n\n<h2 id=\"outline__2\" class=\"wp-block-heading\">reduce\u30e1\u30bd\u30c3\u30c9\u306e\u4f7f\u3044\u65b9<\/h2>\n\n\n\n<p>\u305d\u308c\u3067\u306f\u3055\u3063\u305d\u304f\u3001reduce\u30e1\u30bd\u30c3\u30c9\u306e\u4f7f\u3044\u65b9\u306b\u3064\u3044\u3066\u898b\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n<h3 id=\"outline__2_1\" class=\"wp-block-heading\">\u57fa\u672c\u69cb\u6587<\/h3>\n\n\n\n<p>reduce\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u969b\u306e\u57fa\u672c\u69cb\u6587\u306f\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u8a18\u8ff0\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<p><strong>\u3010\u57fa\u672c\u69cb\u6587\u3011<\/strong><\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-js\" data-lang=\"JavaScript\"><code>\u914d\u5217.reduce(\u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u95a2\u6570, \u521d\u671f\u5024)<\/code><\/pre><\/div>\n\n\n\n<p>\u30e1\u30bd\u30c3\u30c9\u306e\u7b2c\uff11\u5f15\u6570\u306b\u306f\u3001\u8981\u7d20\u306b\u5bfe\u3057\u3066\u884c\u3046\u51e6\u7406\u3092\u5b9a\u7fa9\u3057\u305f\u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u95a2\u6570\u3092\u6307\u5b9a\u3057\u307e\u3059\u3002<br>\u7b2c\uff12\u5f15\u6570\u306b\u306f\u3001\u4efb\u610f\u3067\u51e6\u7406\u3092\u5b9f\u884c\u3059\u308b\u969b\u306e\u521d\u671f\u5024\u3092\u6307\u5b9a\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u307e\u305f\u3001\u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u95a2\u6570\u306e\u5f15\u6570\u306b\u306f\u3001\u4ee5\u4e0b\u306e\uff14\u3064\u3092\u6307\u5b9a\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7b2c1\u5f15\u6570 \u2026 \u51e6\u7406\u4e2d\u306e\u8981\u7d20\u306e\uff11\u3064\u524d\u306e\u8981\u7d20\u304b\u3001\uff11\u3064\u524d\u306e\u30eb\u30fc\u30d7\u3067\u5b9f\u884c\u3055\u308c\u305f\u95a2\u6570\u7d50\u679c\u3001\u3082\u3057\u304f\u306f\u6307\u5b9a\u306e\u521d\u671f\u5024\u306e\u3044\u305a\u308c\u304b<\/li>\n\n\n\n<li>\u7b2c2\u5f15\u6570 \u2026 \u51e6\u7406\u4e2d\u306e\u8981\u7d20<\/li>\n\n\n\n<li>\u7b2c3\u5f15\u6570 \u2026 \u30a4\u30f3\u30c7\u30c3\u30af\u30b9<\/li>\n\n\n\n<li>\u7b2c4\u5f15\u6570 \u2026 \u30e1\u30bd\u30c3\u30c9\u3067\u51e6\u7406\u3057\u3066\u3044\u308b\u914d\u5217<\/li>\n<\/ul>\n\n\n\n<p>\u7b2c\uff11\u5f15\u6570\u306b\u6e21\u3055\u308c\u308b\u5024\u306f\u3001\u30eb\u30fc\u30d7\u56de\u6570\u3084 reduce\u30e1\u30bd\u30c3\u30c9\u306e\u7b2c\uff12\u5f15\u6570\u306e\u6709\u7121\u306b\u3088\u3063\u3066\u5909\u5316\u3057\u307e\u3059\u3002<br>\uff11\u56de\u76ee\u306e\u30eb\u30fc\u30d7\u3067\u306f\u914d\u5217\u306e\u5148\u982d\u8981\u7d20\u3001\u3082\u3057\u304f\u306f reduce\u30e1\u30bd\u30c3\u30c9\u306e\u7b2c\uff12\u5f15\u6570\u306b\u6307\u5b9a\u3057\u305f\u521d\u671f\u5024\u306e\u3069\u3061\u3089\u304b\u304c\u6e21\u3055\u308c\u307e\u3059\u3002<br>\uff12\u56de\u76ee\u4ee5\u964d\u306e\u30eb\u30fc\u30d7\u3067\u306f\u3001\u524d\u56de\u306e\u30eb\u30fc\u30d7\u306e\u51e6\u7406\u7d50\u679c\u304c\u7b2c\uff11\u5f15\u6570\u306b\u6e21\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u7b2c\uff12\u5f15\u6570\u306b\u306f\u3001\u73fe\u5728\u51e6\u7406\u4e2d\u306e\u8981\u7d20\u3092\u6307\u5b9a\u3057\u307e\u3059\u3002<br>\u521d\u671f\u5024\u304c\u3042\u308b\u5834\u5408\u306f\uff10\u756a\u76ee\u306e\u8981\u7d20\u304b\u3089\u3001\u7121\u3044\u5834\u5408\u306f\uff11\u756a\u76ee\u306e\u8981\u7d20\u304b\u3089\u9806\u306b\u683c\u7d0d\u3055\u308c\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u7b2c3\u5f15\u6570\u306b\u306f\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u3092\u3001\u7b2c4\u5f15\u6570\u306b\u306f\u51e6\u7406\u5bfe\u8c61\u306e\u914d\u5217\u3092\u4efb\u610f\u3067\u6307\u5b9a\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<br>\u7b2c3\u5f15\u6570\u306b\u683c\u7d0d\u3055\u308c\u308b\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u306f\u3001\u7b2c\uff12\u5f15\u6570\u306b\u6e21\u3055\u308c\u305f\u8981\u7d20\u306e\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u756a\u53f7\u3068\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u30e1\u30bd\u30c3\u30c9\u306e\u623b\u308a\u5024\u306f\u3001return\u6587\u3092\u4f7f\u7528\u3057\u3066\u6307\u5b9a\u3057\u307e\u3059\u3002<br>\u57fa\u672c\u7684\u306b\u306f\u3001\u305d\u308c\u305e\u308c\u306e\u8981\u7d20\u306b\u5bfe\u3057\u3066\u884c\u3063\u305f\u51e6\u7406\u7d50\u679c\u3092\u6307\u5b9a\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u6307\u5b9a\u3057\u305f\u7d50\u679c\u304c\u3001\u5404\u30eb\u30fc\u30d7\u3054\u3068\u306e\u7b2c\uff11\u5f15\u6570\u306b\u6e21\u3059\u5024\u3068\u3001\u30e1\u30bd\u30c3\u30c9\u306e\u623b\u308a\u5024\u3068\u3057\u3066\u6271\u308f\u308c\u307e\u3059\u3002<\/p>\n\n\n\n<h3 id=\"outline__2_2\" class=\"wp-block-heading\">\u914d\u5217\u306e\u5404\u8981\u7d20\u3092\u5408\u8a08\u3059\u308b<\/h3>\n\n\n\n<p>\u7c21\u5358\u306a\u30b5\u30f3\u30d7\u30eb\u3092\u5143\u306b\u3001reduce\u30e1\u30bd\u30c3\u30c9\u306e\u5b9f\u969b\u306e\u4f7f\u3044\u65b9\u3092\u78ba\u8a8d\u3057\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<br>\u4eca\u56de\u306f\u3001\u914d\u5217\u5185\u306e\u5404\u8981\u7d20\u3092\u5408\u8a08\u3059\u308b\u30b3\u30fc\u30c9\u3092\u4f8b\u3068\u3057\u3066\u7d39\u4ecb\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<p><strong>\u3010\u30b5\u30f3\u30d7\u30eb\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-js\" data-lang=\"JavaScript\"><code>const sampleArray = [1, 2, 3, 4, 5];\n\nconst result = sampleArray.reduce((num1, num2) =&gt; {\n    return num1 + num2;\n});\n\nconsole.log(&quot;\u5408\u8a08\uff1a&quot; + result);<\/code><\/pre><\/div>\n\n\n\n<p><strong>\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-plain\"><code>\u5408\u8a08\uff1a15<\/code><\/pre><\/div>\n\n\n\n<p>reduce\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u5168\u3066\u306e\u8981\u7d20\u3092\u7c21\u5358\u306b\u307e\u3068\u3081\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3057\u305f\u306d\u3002<\/p>\n\n\n\n<p>\u540c\u69d8\u306e\u51e6\u7406\u5185\u5bb9\u3092\u3001forEach\u30e1\u30bd\u30c3\u30c9\u306a\u3069\u3092\u4f7f\u7528\u3057\u3066\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3082\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<p><strong>\u3010\u30b5\u30f3\u30d7\u30eb\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-js\" data-lang=\"JavaScript\"><code>const sampleArray = [1, 2, 3, 4, 5];\n\nlet result = 0;\n\nsampleArray.forEach((num) =&gt; {\n    result += num;\n});<\/code><\/pre><\/div>\n\n\n\n<p>\u305f\u3060\u3057\u3001\u51e6\u7406\u5185\u5bb9\u304c\u8907\u96d1\u5316\u3057\u305f\u5834\u5408\u306b\u3001reduce\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u7528\u3057\u3066\u8a18\u8ff0\u3059\u308b\u30b3\u30fc\u30c9\u3088\u308a\u3082\u53ef\u8aad\u6027\u304c\u4e0b\u304c\u3063\u3066\u3057\u307e\u3046\u3053\u3068\u304c\u3088\u304f\u3042\u308a\u307e\u3059\u3002<br>reduce\u30e1\u30bd\u30c3\u30c9\u3067\u5b9f\u88c5\u3067\u304d\u308b\u5185\u5bb9\u306e\u5834\u5408\u306f\u3001\u306a\u308b\u3079\u304f\u305d\u3061\u3089\u3092\u4f7f\u7528\u3059\u308b\u3088\u3046\u306b\u3059\u308b\u3068\u3044\u3044\u3067\u3057\u3087\u3046\u3002<\/p>\n\n\n\n<h2 id=\"outline__3\" class=\"wp-block-heading\">map\u30e1\u30bd\u30c3\u30c9\u3068reduce\u30e1\u30bd\u30c3\u30c9\u306e\u9055\u3044\u3068\u306f\uff1f<\/h2>\n\n\n\n<p>reduce\u30e1\u30bd\u30c3\u30c9\u3068\u540c\u3058\u3088\u3046\u306b\u3001\u914d\u5217\u306e\u8981\u7d20\u306b\u5bfe\u3057\u3066\u51e6\u7406\u3092\u884c\u3046\u30e1\u30bd\u30c3\u30c9\u306e\uff11\u3064\u306b\u3001map\u30e1\u30bd\u30c3\u30c9\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<p>map\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u914d\u5217\u306e\u5404\u8981\u7d20\u306b\u5bfe\u3057\u3066\u51e6\u7406\u3092\u5b9f\u884c\u3057\u3001\u305d\u306e\u7d50\u679c\u3092\u65b0\u305f\u306a\u914d\u5217\u3068\u3057\u3066\u53d6\u5f97\u3059\u308b\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002<br>\u4e3b\u306b\u4ee5\u4e0b\u306e\uff12\u70b9\u3067\u3001reduce\u30e1\u30bd\u30c3\u30c9\u3068\u52d5\u4f5c\u304c\u7570\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>2\u3064\u306e\u8981\u7d20\u540c\u58eb\u306b\u5bfe\u3057\u3066\u3067\u306f\u306a\u304f\u3001\uff11\u3064\uff11\u3064\u306e\u8981\u7d20\u306b\u5bfe\u3057\u3066\u51e6\u7406\u3092\u884c\u3046<\/li>\n\n\n\n<li>\u5358\u4e00\u306e\u5024\u3067\u306f\u306a\u304f\u3001\u5404\u8981\u7d20\u306e\u51e6\u7406\u7d50\u679c\u3092\u683c\u7d0d\u3057\u305f\u65b0\u305f\u306a\u914d\u5217\u3092\u623b\u308a\u5024\u3068\u3057\u3066\u8fd4\u3059<\/li>\n<\/ul>\n\n\n\n<p>\u4ee5\u4e0b\u306e\u4f8b\u3092\u5143\u306b\u3001\u5b9f\u969b\u306e\u52d5\u304d\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n<p><strong>\u3010\u30b5\u30f3\u30d7\u30eb\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-js\" data-lang=\"JavaScript\"><code>const sampleArray = [1, 2, 3, 4, 5];\n\nconst result = sampleArray.map((num) =&gt; {\n    return num * 10;\n});\n\nconsole.log(result);<\/code><\/pre><\/div>\n\n\n\n<p><strong>\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-plain\"><code>[ 10, 20, 30, 40, 50 ]<\/code><\/pre><\/div>\n\n\n\n<p>reduce\u30e1\u30bd\u30c3\u30c9\u306e\u6642\u3068\u306f\u7570\u306a\u308a\u3001\u914d\u5217\u304c\u623b\u308a\u5024\u3068\u3057\u3066\u8fd4\u3055\u308c\u3066\u3044\u308b\u306e\u304c\u7d50\u679c\u304b\u3089\u3082\u5206\u304b\u308a\u307e\u3059\u306d\u3002<br>\u4e0a\u8a18\u306e\u4f8b\u3067\u306f\u3001\u5404\u8981\u7d20\u309210\u500d\u3059\u308b\u51e6\u7406\u3092\u5b9f\u884c\u3057\u3001\u305d\u306e\u7d50\u679c\u3092\u8981\u7d20\u3068\u3057\u3066\u683c\u7d0d\u3057\u305f\u65b0\u305f\u306a\u914d\u5217\u3092\u53d6\u5f97\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u3053\u306e\u3088\u3046\u306b\u3001\u5168\u3066\u306e\u8981\u7d20\u30921\u3064\u306e\u5024\u3068\u3057\u3066\u307e\u3068\u3081\u308b\u306e\u3067\u306f\u306a\u304f\u3001\u8981\u7d20\u3054\u3068\u306e\u5024\u3092\u5909\u66f4\u3057\u305f\u3044\u5834\u5408\u306b\u4f7f\u7528\u3059\u308b\u306e\u304c\u3001map\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002<br>\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u3044\u5206\u3051\u308b\u969b\u306f\u3001\u623b\u308a\u5024\u306e\u5f62\u5f0f\u3084\u8981\u7d20\u306b\u5bfe\u3059\u308b\u51e6\u7406\u65b9\u6cd5\u306e\u9055\u3044\u3092\u5143\u306b\u3001\u4f7f\u3046\u30e1\u30bd\u30c3\u30c9\u3092\u6c7a\u3081\u308b\u3068\u3044\u3044\u3067\u3057\u3087\u3046\u3002<\/p>\n\n\n\n<h2 id=\"outline__4\" class=\"wp-block-heading\">reduce\u30e1\u30bd\u30c3\u30c9\u306e\u51e6\u7406\u3092\u4e2d\u65ad\u3059\u308b<\/h2>\n\n\n\n<p>\u30eb\u30fc\u30d7\u51e6\u7406\u3092\u3059\u308b\u969b\u306b\u3001\u6761\u4ef6\u306b\u3088\u3063\u3066\u30eb\u30fc\u30d7\u3092\u30b9\u30ad\u30c3\u30d7\u3057\u305f\u308a\u3001\u4e2d\u65ad\u3057\u305f\u3044\u3068\u3044\u3063\u305f\u30b1\u30fc\u30b9\u306f\u3088\u304f\u3042\u308b\u3053\u3068\u304b\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u3057\u304b\u3057\u306a\u304c\u3089\u3001reduce\u30e1\u30bd\u30c3\u30c9\u306f\u4ed5\u69d8\u4e0a\u3001continue \u3084 break \u3092\u30d6\u30ed\u30c3\u30af\u5185\u3067\u4f7f\u7528\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u305b\u3093\u3002<br>\u305d\u306e\u305f\u3081\u3001\u30b9\u30ad\u30c3\u30d7\u3084\u4e2d\u65ad\u3092\u3059\u308b\u5834\u5408\u306f\u4ed6\u306e\u65b9\u6cd5\u3067\u4ee3\u7528\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u305d\u306e\u56de\u306e\u30eb\u30fc\u30d7\u306e\u307f\u3092\u30b9\u30ad\u30c3\u30d7\u3057\u305f\u3044\u5834\u5408\u306f\u3001\u623b\u308a\u5024\u3067\u524d\u56de\u306e\u51e6\u7406\u7d50\u679c\u3092\u305d\u306e\u307e\u307e\u6b21\u306e\u30eb\u30fc\u30d7\u3078\u3068\u8fd4\u3059\u3088\u3046\u306b\u3057\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n<p><strong>\u3010\u30b5\u30f3\u30d7\u30eb\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-js\" data-lang=\"JavaScript\"><code>const sampleArray = [1, 2, 3, 4, 5];\n\nconst result = sampleArray.reduce((num1, num2) =&gt; {\n    if (num2 === 3) {\n        return num1;\n    } else {\n        return num1 + num2;\n    }\n});\n\nconsole.log(result);<\/code><\/pre><\/div>\n\n\n\n<p><strong>\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-plain\"><code>12<\/code><\/pre><\/div>\n\n\n\n<p>\u51e6\u7406\u3092\u305d\u306e\u307e\u307e\u4e2d\u65ad\u3055\u305b\u305f\u3044\u5834\u5408\u306f\u3001splice\u30e1\u30bd\u30c3\u30c9\u306a\u3069\u3068\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u4ee3\u66ff\u53ef\u80fd\u3067\u3059\u3002<\/p>\n\n\n\n<p><strong>\u3010\u30b5\u30f3\u30d7\u30eb\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-js\" data-lang=\"JavaScript\"><code>const sampleArray = [1, 2, 3, 4, 5];\n\nconst result = sampleArray.reduce((num1, num2) =&gt; {\n\n    if (num1 &gt; 5) {\n        sampleArray.splice(0);\n        return num1\n    }\n    \n    return num1 + num2;\n});\n\nconsole.log(result);<\/code><\/pre><\/div>\n\n\n\n<p><strong>\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n\n\n\n<div class=\"hcb_wrap\"><pre class=\"prism line-numbers lang-plain\"><code>6<\/code><\/pre><\/div>\n\n\n\n<p>\u305f\u3060\u3057\u3001splice\u30e1\u30bd\u30c3\u30c9\u306f\u7834\u58ca\u7684\u30e1\u30bd\u30c3\u30c9\u3067\u3042\u308b\u95a2\u4fc2\u4e0a\u3001\u5143\u306e\u914d\u5217\u306e\u5185\u5bb9\u304c\u5909\u308f\u3063\u3066\u3057\u307e\u3046\u30c7\u30e1\u30ea\u30c3\u30c8\u304c\u3042\u308b\u305f\u3081\u3001\u5fc5\u8981\u306b\u5fdc\u3058\u3066\u914d\u5217\u306e\u30b3\u30d4\u30fc\u3092\u884c\u3046\u306a\u3069\u3057\u3066\u5bfe\u7b56\u3059\u308b\u3088\u3046\u306b\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n\n\n\n<h2 id=\"outline__5\" class=\"wp-block-heading\">\u307e\u3068\u3081<\/h2>\n\n\n\n<p>\u4eca\u56de\u306f\u3001reduce\u30e1\u30bd\u30c3\u30c9\u306e\u4f7f\u3044\u65b9\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u307e\u3057\u305f\u3002<\/p>\n\n\n\n<p>JavaScript\u306e\u914d\u5217\u306b\u306f\u3001reduce\u30e1\u30bd\u30c3\u30c9\u3082\u542b\u3081\u3001\u5b9f\u884c\u3057\u305f\u3044\u76ee\u7684\u306b\u5408\u308f\u305b\u305f\u30e1\u30bd\u30c3\u30c9\u304c\u3044\u304f\u3064\u3082\u7528\u610f\u3055\u308c\u3066\u3044\u307e\u3059\u3002<br>\u30b1\u30fc\u30b9\u306b\u3088\u3063\u3066\u306f\u3001for\u6587\u306a\u3069\u3092\u4f7f\u3046\u3088\u308a\u3082\u52b9\u7387\u7684\u306b\u30b3\u30fc\u30c9\u3092\u8a18\u8ff0\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u306e\u3067\u3001\u305c\u3072\u7a4d\u6975\u7684\u306b\u6d3b\u7528\u3057\u3066\u3044\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n<h2 id=\"outline__6\" class=\"wp-block-heading\">JavaScript\u306e\u52c9\u5f37\u65b9\u6cd5\u306f\uff1f<\/h2>\n\n\n<p>\u66f8\u7c4d\u3084\u30a4\u30f3\u30bf\u30fc\u30cd\u30c3\u30c8\u3067\u5b66\u7fd2\u3059\u308b\u65b9\u6cd5\u304c\u3042\u308a\u307e\u3059\u3002\u6628\u4eca\u3067\u306f\u3001YouTube\u306a\u3069\u306e\u52d5\u753b\u30b5\u30a4\u30c8\u3084\u30a8\u30f3\u30b8\u30cb\u30a2\u306e\u30b3\u30df\u30e5\u30cb\u30c6\u30a3\u30b5\u30a4\u30c8\u306a\u3069\u3082\u5145\u5b9f\u3057\u3066\u3044\u3066\u591a\u304f\u306e\u60c5\u5831\u304c\u624b\u306b\u5165\u308a\u307e\u3059\u3002<br \/>\u305d\u3057\u3066\u3001\u3088\u308a\u52b9\u7387\u7684\u306b\u77e5\u8b58\u30fb\u30b9\u30ad\u30eb\u3092\u7fd2\u5f97\u3059\u308b\u306b\u306f\u3001\u77e5\u8b58\u3092\u3064\u3051\u306a\u304c\u3089\u5b9f\u969b\u306b\u624b\u3092\u52d5\u304b\u3057\u3066\u307f\u308b\u306a\u3069\u3001\u30a4\u30f3\u30d7\u30c3\u30c8\u3068\u30a2\u30a6\u30c8\u30d7\u30c3\u30c8\u3092\u7e70\u308a\u8fd4\u3057\u3066\u3044\u304f\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002\u7279\u306b\u72ec\u5b66\u306e\u5834\u5408\u306f\u3001\u6709\u8b58\u8005\u306b\u8cea\u554f\u304c\u3067\u304d\u305f\u308a\u30d5\u30a3\u30fc\u30c9\u30d0\u30c3\u30af\u3092\u3082\u3089\u3048\u308b\u3088\u3046\u306a\u74b0\u5883\u304c\u3042\u308b\u3068\u3001\u7406\u89e3\u5ea6\u304c\u6df1\u307e\u308b\u3067\u3057\u3087\u3046\u3002<\/p>\n<p>\u305f\u3060\u3001JavaScript\u306b\u9650\u3089\u305a\u3001IT\u30b9\u30ad\u30eb\u3092\u8eab\u306b\u3064\u3051\u308b\u969b\u3001\u3069\u3046\u3057\u3066\u3082\u8ab2\u984c\u306b\u3076\u3064\u304b\u3063\u3066\u3057\u307e\u3046\u3053\u3068\u306f\u3042\u308a\u307e\u3059\u3088\u306d\u3002\u7279\u306b\u72ec\u5b66\u3060\u3068\u3001\u308f\u304b\u3089\u306a\u3044\u90e8\u5206\u3092\u30d7\u30ed\u306b\u8cea\u554f\u3067\u304d\u308b\u6a5f\u4f1a\u3092\u78ba\u4fdd\u3057\u306b\u304f\u304f\u3001\u30e2\u30c1\u30d9\u30fc\u30b7\u30e7\u30f3\u304c\u7d9a\u304d\u306b\u304f\u3044\u3068\u3044\u3046\u5074\u9762\u304c\u3042\u308a\u307e\u3059\u3002\u72ec\u5b66\u3067\u30e2\u30c1\u30d9\u30fc\u30b7\u30e7\u30f3\u3092\u7dad\u6301\u3059\u308b\u81ea\u4fe1\u304c\u306a\u3044\u4eba\u306b\u306f\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u30b9\u30af\u30fc\u30eb\u3068\u3044\u3046\u624b\u3082\u3042\u308a\u307e\u3059\u3002\u8cbb\u7528\u306f\u639b\u304b\u308a\u307e\u3059\u304c\u3001\u305d\u306e\u5206\u30b9\u30ad\u30eb\u3092\u8eab\u306b\u3064\u3051\u3084\u3059\u3044\u3067\u3059\u3002\u3057\u3063\u304b\u308a\u3068\u77e5\u8b58\u30fb\u30b9\u30ad\u30eb\u3092\u7fd2\u5f97\u3057\u3066\u5b9f\u8df5\u306b\u6d3b\u304b\u3057\u305f\u3044\u3068\u3044\u3046\u4eba\u306f\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u30b9\u30af\u30fc\u30eb\u304c\u304a\u3059\u3059\u3081\u3067\u3059\u3002<\/p>\n<p><span class=\"markerYellow\"><strong>\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u30b9\u30af\u30fc\u30eb\u306a\u3089\u30c6\u30c3\u30af\u30de\u30cb\u30a2\u304c\u304a\u3059\u3059\u3081\uff01<\/strong><\/span><\/p>\n\n\n<img decoding=\"async\" src=\"https:\/\/web-img.rensa.jp.net\/rensa\/images\/techmania\/thumbnail\/images\/yuudou.png\" alt=\"\" class=\"post-img\" loading=\"lazy\">\n\n\n<p>IT\u30b9\u30ad\u30eb\u9700\u8981\u306e\u9ad8\u307e\u308a\u3068\u3068\u3082\u306b\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u30b9\u30af\u30fc\u30eb\u3082\u5897\u3048\u307e\u3057\u305f\u3002\u3057\u304b\u3057\u3001\u3069\u306e\u30b9\u30af\u30fc\u30eb\u306b\u901a\u3046\u3079\u304d\u304b\u8ff7\u3063\u3066\u3057\u307e\u3046\u4eba\u3082\u3044\u308b\u3067\u3057\u3087\u3046\u3002\u305d\u3093\u306a\u65b9\u306b\u306f\u30c6\u30c3\u30af\u30de\u30cb\u30a2\u3092\u304a\u3059\u3059\u3081\u3057\u307e\u3059\uff01\u3053\u308c\u307e\u3067\u591a\u304f\u306eIT\u30a8\u30f3\u30b8\u30cb\u30a2\u3092\u80b2\u6210\u30fb\u8f29\u51fa\u3057\u3066\u304d\u305f\u30c6\u30c3\u30af\u30de\u30cb\u30a2\u3067\u3082\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u30b9\u30af\u30fc\u30eb\u3092\u958b\u8b1b\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<div class=\"bgBox\">\n<p><strong>\uff1c\u30c6\u30c3\u30af\u30de\u30cb\u30a2\u306e\u7279\u5fb4\uff1e<\/strong><br \/><strong>\u30fb\u305f\u3057\u304b\u306a\u80b2\u6210\u5b9f\u7e3e\u3068\u89aa\u8eab\u306a\u6559\u80b2\u3000\uff5e\u30bb\u30ab\u30f3\u30c9\u30ad\u30e3\u30ea\u30a2\u3092\u5168\u529b\u652f\u63f4\uff5e<\/strong><br \/><strong>\u30fb\u8b1b\u5e2b\u304c\u73fe\u5f79\u30a8\u30f3\u30b8\u30cb\u30a2\u3000\uff5e\u201c\u672c\u5f53\u201d\u306e\u958b\u767a\u30ce\u30a6\u30cf\u30a6\u3092\u76f4\u306b\u5b66\u3079\u308b\uff5e<\/strong><br \/><strong>\u30fb\u5c02\u5c5e\u8b1b\u5e2b\u304c\u5b66\u7fd2\u3092\u5fb9\u5e95\u30b5\u30dd\u30fc\u30c8\u3000\uff5e\u300c\u308f\u304b\u3089\u306a\u3044\u300d\u3092\u5fb9\u5e95\u89e3\u6c7a\uff5e<\/strong><br \/><strong>\u30fb\u5b9f\u52d9\u30d9\u30fc\u30b9\u3067\u30b9\u30ad\u30eb\u3092\u7fd2\u5f97\u3000\uff5e\u5b9f\u8df5\u7684\u306a\u51dd\u7e2e\u30ab\u30ea\u30ad\u30e5\u30e9\u30e0\uff5e<\/strong><\/p>\n<\/div>\n<p>\u3053\u306e\u3088\u3046\u306a\u7279\u5fb4\u3092\u6301\u3064\u30c6\u30c3\u30af\u30de\u30cb\u30a2\u306fIT\u30a8\u30f3\u30b8\u30cb\u30a2\u306e\u30b9\u30bf\u30fc\u30c8\u30e9\u30a4\u30f3\u3068\u3057\u3066\u6700\u9069\u3067\u3059\u3002<br \/>\u8a71\u3092\u805e\u304d\u305f\u3044\u30fb\u8a73\u3057\u304f\u77e5\u308a\u305f\u3044\u3068\u3044\u3046\u65b9\u306f<a href=\"https:\/\/techmania.jp\/lp\/2\" target=\"_blank\" rel=\"noopener\">\u3053\u3061\u3089<\/a>\u304b\u3089\u304a\u6c17\u8efd\u306b\u304a\u554f\u3044\u5408\u308f\u305b\u304f\u3060\u3055\u3044\u3002<\/p>","protected":false},"excerpt":{"rendered":"JavaScript\u306e\u914d\u5217\u306b\u306f\u3001\u5168\u3066\u306e\u8981\u7d20\u3092\uff11\u3064\u306b\u307e\u3068\u3081\u305f\u3044\u5834\u5408\u306b\u4fbf\u5229\u306a \u300creduce\u300d \u3068\u3044\u3046\u30e1\u30bd\u30c3\u30c9\u304c\u65e2\u5b58\u3067\u7528\u610f\u3055\u308c\u3066\u3044\u307e\u3059\u3002 \u4eca\u56de\u306f\u3001reduce\u30e1\u30bd\u30c3\u30c9\u306e\u8a73\u3057\u3044\u4f7f\u3044\u65b9\u306b\u3064\u3044\u3066\u89e3\u8aac\u3092\u3057\u3066\u3044\u304d\u305f\u3044\u3068\u601d\u3044\u307e\u3059\u3002 JavaScript\u306ereduce\u30e1\u30bd\u30c3\u30c9\u3068\u306f\uff1f reduce\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u914d\u5217\u5185\u306e\u8981\u7d20\u30921\u3064\u306e\u5024\u3068\u3057\u3066\u307e\u3068\u3081\u305f\u3044\u5834\u5408\u306b\u6d3b\u7528\u3067\u304d\u308b\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002\u914d\u5217\u5185\u306e\u96a3\u308a\u5408\u3046\u8981\u7d20\u306b\u5bfe\u3057\u3066\u95a2\u6570\u3092\u5b9f\u884c\u3059\u308b [&hellip;]","protected":false},"author":11,"featured_media":10106,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"https:\/\/web-img.rensa.jp.net\/images\/techmania\/thumbnail\/images\/javascript-reduce.webp","fifu_image_alt":"\u3010JavaScript\u5165\u9580\u3011reduce\u30e1\u30bd\u30c3\u30c9\u3067\u914d\u5217\u3092\u4e00\u3064\u306e\u5024\u306b\u7e2e\u5c0f\u3059\u308b","footnotes":""},"categories":[15],"tags":[17],"class_list":["post-10102","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-programming","tag-javascript"],"_links":{"self":[{"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/posts\/10102","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/comments?post=10102"}],"version-history":[{"count":2,"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/posts\/10102\/revisions"}],"predecessor-version":[{"id":10105,"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/posts\/10102\/revisions\/10105"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/media\/10106"}],"wp:attachment":[{"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/media?parent=10102"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/categories?post=10102"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/techmania.jp\/blog\/wp-json\/wp\/v2\/tags?post=10102"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}