{"id":332,"date":"2021-04-22T16:01:14","date_gmt":"2021-04-22T07:01:14","guid":{"rendered":"https:\/\/test.freedoming.jp\/wp\/?p=332"},"modified":"2021-04-22T16:01:14","modified_gmt":"2021-04-22T07:01:14","slug":"10023","status":"publish","type":"post","link":"https:\/\/test.freedoming.jp\/wp\/tech\/10023\/","title":{"rendered":"JavaScript\u306emap,filter\u3092\u7528\u3044\u305f\u914d\u5217\u51e6\u7406\u306b\u3064\u3044\u3066"},"content":{"rendered":"

\u4eca\u56de\u306f\u8868\u984c\u306e\u901a\u308aJavaScript\u306eArray.prototype.map()\u3001Array.prototype.filter()\u3092\u7528\u3044\u305f\u914d\u5217\u51e6\u7406\u306b\u3064\u3044\u3066\u304a\u8a71\u3057\u307e\u3059\u3002<\/p>\n

\u3056\u3063\u304f\u308a\u8aac\u660e\u3059\u308b\u3068\u3001map\u306f\u300c\u914d\u5217\u306e\u5168\u8981\u7d20\u306b\u5bfe\u3057\u3066\u6307\u5b9a\u306e\u95a2\u6570\u3092\u9069\u7528\u3057\u305f\u3001\u65b0\u3057\u3044\u914d\u5217\u3092\u8fd4\u3059\u300d\u30e1\u30bd\u30c3\u30c9\u3067\u3001
\nfilter\u306f\u300c\u914d\u5217\u306e\u5168\u8981\u7d20\u306b\u5bfe\u3057\u3066\u6307\u5b9a\u306e\u95a2\u6570\u3092\u9069\u7528\u3057\u3001true\u306e\u8981\u7d20\u306e\u307f\u6b8b\u3057\u305f\u65b0\u3057\u3044\u914d\u5217\u3092\u8fd4\u3059\u300d\u30e1\u30bd\u30c3\u30c9\u3068\u306a\u308a\u307e\u3059\u3002
\n\u3069\u3061\u3089\u3082\u6307\u5b9a\u306e\u95a2\u6570\u3092\u5168\u8981\u7d20\u306b\u9069\u7528\u3059\u308b\u3082\u306e\u3067\u3059\u304c\u3001\u3053\u308c\u3089\u306e\u30e1\u30bd\u30c3\u30c9\u81ea\u4f53\u306f\u300c\u65b0\u3057\u3044\u914d\u5217\u3092\u8fd4\u3059\uff08\uff1d\u5143\u306e\u914d\u5217\u3092\u5909\u66f4\u3057\u306a\u3044\uff09\u300d\u4e8b\u3082\u5927\u304d\u306a\u30dd\u30a4\u30f3\u30c8\u3067\u3059\u3002<\/p>\n

 <\/p>\n

\u30fbmap
\n[1, 2, 3, 4, 5].map(e => e + 10) \/\/ => [11, 12 13, 14, 15]<\/p>\n

\/\/ \u3053\u3061\u3089\u306e\u4f8b\u3082\u540c\u3058
\nconst addTen = e => e + 10
\n[1, 2, 3, 4, 5].map(addTen)<\/p>\n

 <\/p>\n

\u4e0a\u8a18\u306f\u914d\u5217\u306e\u5168\u8981\u7d20\u306b10\u3092\u8db3\u3059\u95a2\u6570\u3092\u9069\u7528\u3059\u308b\u4f8b\u3067\u3059\u3002
\nfunction (\u73fe\u5728\u306e\u8981\u7d20) {} \u306e\u3088\u3046\u306a\u30011\u8981\u7d20\u53d7\u3051\u53d6\u308b\u95a2\u6570\u3092\u6e21\u3057\u3066\u3084\u308b\u306e\u304c\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\u3067\u3059\u3002
\n\u307e\u305f\u3001map\u306f\u65b0\u3057\u3044\u914d\u5217\u3092\u8fd4\u5374\u3059\u308b\u306e\u3067\u3001map\u3092\u30c1\u30a7\u30a4\u30f3\u3057\u3066\u66f4\u306b\u5225\u306e\u51e6\u7406\u3092\u52a0\u3048\u3066\u3084\u308b\u3053\u3068\u3082\u3067\u304d\u307e\u3059\u3002<\/p>\n

 <\/p>\n

type Obj = {
\nname: string,
\npostcode: string
\n}
\nconst obj: Obj = {
\nname: ‘Alice’,
\npostcode: ‘1000000’
\n}<\/p>\n

 <\/p>\n

\u4f8b\u3048\u3070\u3001\u4e0a\u8a18\u306e\u3088\u3046\u306a\u300cXXXXXXX\u300d\u5f62\u5f0f\u306e\u90f5\u4fbf\u756a\u53f7\u3092\u6301\u3064\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u914d\u5217\u304c\u3042\u3063\u305f\u3068\u3057\u3066\u3001
\n\u305d\u3053\u304b\u3089\u90f5\u4fbf\u756a\u53f7\u3060\u3051\u3092\u629c\u304d\u53d6\u308a\u3001\u66f4\u306b\u300c\u3012XXX-XXXX\u300d\u5f62\u5f0f\u306b\u30d5\u30a9\u30fc\u30de\u30c3\u30c8\u3057\u305f\u3044\u5834\u5408\u306f<\/p>\n

 <\/p>\n

const arr: Obj[] = [\/* Obj\u3092\u8981\u7d20\u306b\u6301\u3064\u914d\u5217 *\/]
\nconst formatPostcode = e => \/* 8\u6841\u306e\u90f5\u4fbf\u756a\u53f7\u3092\u300c\u3012XXX-XXXX\u300d\u5f62\u5f0f\u306b\u30d5\u30a9\u30fc\u30de\u30c3\u30c8\u3059\u308b\u95a2\u6570 *\/
\nconst postcodes = arr.map(e => e.postcode).map(formatPostcode)<\/p>\n

 <\/p>\n

\u306e\u3088\u3046\u306b\u66f8\u3051\u307e\u3059\u3002
\n\u8ffd\u52a0\u3068\u3057\u3066\u3001map\u306b\u6e21\u3059\u95a2\u6570\u306f\u7701\u7565\u53ef\u80fd\u306a\u7b2c2\u5f15\u6570\u3068\u7b2c3\u5f15\u6570\u3092\u6301\u3066\u3066\u3001\u305d\u308c\u305e\u308c\u300c\u73fe\u5728\u306e\u914d\u5217\u306e\u6dfb\u5b57\u300d\u300cmap\u304c\u9069\u7528\u3055\u308c\u3066\u3044\u308b\u914d\u5217\u305d\u306e\u3082\u306e\u300d\u3092\u53d7\u3051\u53d6\u308a\u307e\u3059\u3002
\nn\u756a\u76ee\u306e\u8981\u7d20\u306f\u9055\u3046\u51e6\u7406\u3092\u3059\u308b\u3060\u3068\u304b\u3001\u914d\u5217\u306e\u9577\u3055\u304c\u898b\u305f\u3044\u6642\u3060\u3068\u304b\u306b\u4f7f\u3048\u307e\u3059\u3002<\/p>\n

 <\/p>\n

\u30fbfilter
\n[1, 2, 3, 4, 5, 6].filter(e => e % 2 === 0) \/\/ => [2, 4, 6]<\/p>\n

 <\/p>\n

\u4e0a\u8a18\u306ffilter\u3092\u9069\u7528\u3059\u308b\u914d\u5217\u304b\u3089\u3001\u5076\u6570\u306e\u8981\u7d20\u306e\u307f\u3092\u62bd\u51fa\u3059\u308b\u4f8b\u3067\u3059\u3002
\n`filter`\u304c\u5f15\u6570\u3068\u3057\u3066\u53d7\u3051\u53d6\u308b\u95a2\u6570\u306e\u5f15\u6570\u306e\u5f62\u5f0f\uff08\u7b2c1\u5f15\u6570\u304c\u73fe\u5728\u306e\u8981\u7d20\u3001\u7701\u7565\u53ef\u80fd\u306a\u7b2c2, \u7b2c3\u5f15\u6570\uff09\u306f\u540c\u3058\u3067\u3059\u304c\u3001
\n\u53d7\u3051\u53d6\u308b\u95a2\u6570\u304c\u771f\u507d\u5024\uff08true, false\uff09\u3092\u8fd4\u3059\u5fc5\u8981\u304c\u3042\u308b\u70b9\u304c\u7570\u306a\u308a\u307e\u3059\u3002
\nmap\u3068\u540c\u69d8\u65b0\u3057\u3044\u914d\u5217\u3092\u8fd4\u5374\u3059\u308b\u306e\u3067\u3001\u66f4\u306bmap\u3084filter\u3092\u30c1\u30a7\u30a4\u30f3\u3067\u304d\u307e\u3059\u3002<\/p>\n

 <\/p>\n

\/\/ Obj\u306e\u578b\u306fmap\u306e\u4f8b\u3068\u540c\u69d8
\nconst arr: Obj[] = [\/* Obj\u3092\u8981\u7d20\u306b\u6301\u3064\u914d\u5217 *\/]
\nconst arr2 = arr.filter(e => e.postcode === ‘1020072’).map(e => e.name)<\/p>\n

 <\/p>\n

\u4e0a\u8a18\u306f\u90f5\u4fbf\u756a\u53f7\u304c1020072\u306e\u8981\u7d20\u3092\u629c\u304d\u51fa\u3057\u3001\u3055\u3089\u306b\u305d\u306e\u8981\u7d20\u306e\u540d\u524d\u3060\u3051\u3092\u6b8b\u3059\u51e6\u7406\u306e\u4f8b\u3067\u3059\u3002<\/p>\n

 <\/p>\n

const isLessThanSix = e => \/* 6\u5b57\u3088\u308a\u5c11\u306a\u3044\u306a\u3089\u8b66\u544a\u6587\u3092\u8fd4\u5374\u3001\u305d\u3046\u3067\u306a\u3051\u308c\u3070”\u3092\u8fd4\u5374\u3059\u308b\u95a2\u6570 *\/
\nconst notContainsUpperCase = e => \/* \u5927\u6587\u5b57\u3092\u542b\u3093\u3067\u3044\u306a\u3051\u308c\u3070\u8b66\u544a\u6587\u3092\u8fd4\u5374\u3001\u305d\u3046\u3067\u306a\u3051\u308c\u3070”\u3092\u8fd4\u5374\u3059\u308b\u95a2\u6570 *\/
\nconst notContainsLowerCase = e => \/* \u5c0f\u6587\u5b57\u3092\u542b\u3093\u3067\u3044\u306a\u3051\u308c\u3070\u8b66\u544a\u6587\u3092\u8fd4\u5374\u3001\u305d\u3046\u3067\u306a\u3051\u308c\u3070”\u3092\u8fd4\u5374\u3059\u308b\u95a2\u6570 *\/
\nconst validation = text => {
\nreturn [isLessThanSix, notContainsUpperCase, notContainsLowerCase]
\n.map(f => f(text))
\n.filter(Boolean)
\n}
\nconst invalidPassword = validation(‘aaaaa’) \/\/ => [‘6\u5b57\u3088\u308a\u5c11\u306a\u3044\u3068\u304d\u306e\u8b66\u544a\u6587’, ‘\u5927\u6587\u5b57\u3092\u542b\u3093\u3067\u3044\u306a\u3044\u3068\u304d\u306e\u8b66\u544a\u6587’]
\nconst validPassword = validation(‘aaaaaA’) \/\/ => []<\/p>\n

 <\/p>\n

\u3082\u3046\u4e00\u4f8b\u3001map, filter\u3092\u7528\u3044\u305f\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u306e\u4f8b\u3067\u3059\u3002
\n\u30a8\u30e9\u30fc\u6587\u3092\u8fd4\u3059\u95a2\u6570\u3092\u914d\u5217\u306b\u3057\u3066\u3001\u300c\u95a2\u6570 => \u30a8\u30e9\u30fc\u6587\uff08\u307e\u305f\u306f”\uff09\u300d\u306bmap\u3057\u3001”\u3067\u306a\u3044\u8981\u7d20\u3092filter\u3057\u3066\u3044\u307e\u3059\u3002
\nmap\u3092\u4f7f\u3046\u3053\u3068\u3067\u300c\u3053\u3053\u306f\u914d\u5217\u3092\u5909\u66f4\u3057\u3066\u3044\u307e\u3059\u300d\u3001filter\u3092\u4f7f\u3046\u3053\u3068\u3067\u300c\u3053\u3053\u306f\u914d\u5217\u3092\u30d5\u30a3\u30eb\u30bf\u30ea\u30f3\u30b0\u3057\u3066\u3044\u307e\u3059\u300d\u3068\u3044\u3046\u306e\u304c\u660e\u78ba\u306b\u306a\u308b\u306e\u3067\u3001
\n\u540c\u69d8\u306e\u914d\u5217\u51e6\u7406\u3092for\u3067\u884c\u3063\u305f\u5834\u5408\u3068\u6bd4\u3079\u3001\u30b3\u30fc\u30c9\u304c\u5ba3\u8a00\u7684\u3067\u7c21\u6f54\u306b\u8a18\u8ff0\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308b\u306e\u304c\u30dd\u30a4\u30f3\u30c8\u9ad8\u3044\u3067\u3059\u3002
\n\u4eca\u65e5\u3001JavaScript\u306b\u304a\u3051\u308bmap, filter\u3068\u540c\u69d8\u306e\u6a5f\u80fd\u306f\u8272\u3005\u306a\u8a00\u8a9e\u306b\uff08\u540d\u524d\u306f\u9055\u3048\u3069\uff09\u642d\u8f09\u3055\u308c\u3066\u3044\u308b\u306e\u3067\u3001\u662f\u975e\u4f7f\u3063\u3066\u307f\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n

 <\/p>\n

\u53c2\u8003\uff1aArray.prototype.map() – JavaScript | MDN –\u00a0https:\/\/developer.mozilla.org\/ja\/docs\/Web\/JavaScript\/Reference\/Global_Objects\/Array\/map<\/a>
\nArray.prototype.filter() – JavaScript | MDN –\u00a0https:\/\/developer.mozilla.org\/ja\/docs\/Web\/JavaScript\/Reference\/Global_Objects\/Array\/filter<\/a><\/p>\n

 <\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

\u4eca\u56de\u306f\u8868\u984c\u306e\u901a\u308aJavaScript\u306eArray.prototype.map()\u3001Array.prototype.filter()\u3092\u7528\u3044\u305f\u914d\u5217\u51e6\u7406\u306b\u3064\u3044\u3066\u304a\u8a71\u3057\u307e\u3059\u3002 \u3056\u3063\u304f\u308a\u8aac\u660e\u3059\u308b\u3068\u3001map\u306f\u300c\u914d\u5217\u306e\u5168\u8981\u7d20\u306b\u5bfe\u3057\u3066\u6307 […]<\/p>\n","protected":false},"author":12,"featured_media":334,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[3],"tags":[],"_links":{"self":[{"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/posts\/332"}],"collection":[{"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/comments?post=332"}],"version-history":[{"count":1,"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/posts\/332\/revisions"}],"predecessor-version":[{"id":333,"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/posts\/332\/revisions\/333"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/media\/334"}],"wp:attachment":[{"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/media?parent=332"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/categories?post=332"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/test.freedoming.jp\/wp\/wp-json\/wp\/v2\/tags?post=332"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}