{"id":5249,"date":"2022-01-25T10:13:07","date_gmt":"2022-01-25T01:13:07","guid":{"rendered":"https:\/\/akamist.com\/blog\/?p=5249"},"modified":"2022-01-25T10:13:07","modified_gmt":"2022-01-25T01:13:07","slug":"typescript-object%e5%9e%8b%e3%81%aelength%e3%82%92%e5%8f%96%e5%be%97%e3%81%99%e3%82%8b%e3%81%a8ts2339%e3%82%a8%e3%83%a9%e3%83%bc%e3%81%8c%e7%99%ba%e7%94%9f%e3%81%99%e3%82%8b","status":"publish","type":"post","link":"https:\/\/akamist.com\/blog\/archives\/5249","title":{"rendered":"[TypeScript] Object\u578b\u306elength\u3092\u53d6\u5f97\u3059\u308b\u3068TS2339\u30a8\u30e9\u30fc\u304c\u767a\u751f\u3059\u308b"},"content":{"rendered":"<h2>\u767a\u751f\u3057\u305f\u30a8\u30e9\u30fc<\/h2>\n<p>TypeScript\u3067\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u578b\u306e\u5909\u6570\u306b\u5bfe\u3057\u3066length\u3092\u53d6\u5f97\u3057\u3088\u3046\u3068\u3059\u308b\u3068\u3001<code>TS2339<\/code>\u30a8\u30e9\u30fc\u304c\u767a\u751f\u3059\u308b\u3002<\/p>\n<ul>\n<li>\u30b3\u30fc\u30c9(react)<\/li>\n<\/ul>\n<pre><code class=\"language-js\">type UsersType {\n   ...\n};\n\nconst [user, setUser] = React.useState&lt;UserType&gt;();\nif (user.length &lt;= 0) {   \u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\/\/ \u3053\u3053\u3067TS2339\u30a8\u30e9\u30fc\n   ...\n}\n<\/code><\/pre>\n<ul>\n<li>\u767a\u751f\u3057\u305f\u30a8\u30e9\u30fc<\/li>\n<\/ul>\n<pre><code class=\"language-js\">TS2339: Property 'length' does not exist on type 'UserType'.\n<\/code><\/pre>\n<h2>\u7406\u7531<\/h2>\n<p>\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u6b63\u3057\u304f\u3066\u3001(Array\u3068\u306f\u7570\u306a\u308a)\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u578b\u306e\u5909\u6570\u306b\u306flength\u306e\u30d7\u30ed\u30d1\u30c6\u30a3\u304c\u5b58\u5728\u3057\u306a\u3044\u3002<\/p>\n<h2>\u5bfe\u51e6<\/h2>\n<p>\u672c\u6765\u884c\u3044\u305f\u304b\u3063\u305f\u3053\u3068\u306f\u3001\u8a72\u5f53\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u30ad\u30fc\u304c1\u3064\u4ee5\u4e0a\u5b58\u5728\u3059\u308b\u304b\u3060\u3063\u305f\u305f\u3081\u3001\u4ee5\u4e0b\u306e\u5f62\u3067keys\u306e\u914d\u5217\u3092\u53d6\u5f97\u3057\u305f\u4e0a\u3067length\u306e\u30d7\u30ed\u30d1\u30c6\u30a3\u3092\u53c2\u7167\u3057\u305f\u3068\u3053\u308d\u30a8\u30e9\u30fc\u304c\u89e3\u6d88\u3057\u305f\u3002<\/p>\n<pre><code class=\"language-js\">if (user.length &lt;= 0) {\n\n\u2193\n\nif (Object.keys(user).length &lt;= 0) {\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u767a\u751f\u3057\u305f\u30a8\u30e9\u30fc TypeScript\u3067\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u578b\u306e\u5909\u6570\u306b\u5bfe\u3057\u3066length\u3092\u53d6\u5f97\u3057\u3088\u3046\u3068\u3059\u308b\u3068\u3001TS2339\u30a8\u30e9\u30fc\u304c\u767a\u751f\u3059\u308b\u3002 \u30b3\u30fc\u30c9(react) type UsersType { ... }; const [u [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":5251,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[303,302],"aioseo_notices":[],"jetpack_featured_media_url":"https:\/\/akamist.com\/blog\/wp-content\/uploads\/2022\/01\/icon_typescript.png","jetpack-related-posts":[{"id":2270,"url":"https:\/\/akamist.com\/blog\/archives\/2270","url_meta":{"origin":5249,"position":0},"title":"[Angular]\"No provider for xxx\"\u30a8\u30e9\u30fc\u304c\u767a\u751f\u3059\u308b\u3068\u304d\u306e\u5bfe\u51e6\u6cd5","date":"2018\u5e743\u670826\u65e5","format":false,"excerpt":"## \u767a\u751f\u3057\u305f\u30a8\u30e9\u30fc app.component.ts\u3067\u3001\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u306bHttp\u578b\u306e\u5f15\u6570\u3092\u6307\u5b9a\u3059\u308b\u2026","rel":"","context":"Angular","img":{"alt_text":"","src":"https:\/\/i0.wp.com\/akamist.com\/blog\/wp-content\/uploads\/2018\/03\/icon_angular.png?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":5503,"url":"https:\/\/akamist.com\/blog\/archives\/5503","url_meta":{"origin":5249,"position":1},"title":"styled-components\u3092import\u3059\u308b\u3068TS7016\u30a8\u30e9\u30fc\u304c\u51fa\u308b\u3068\u304d","date":"2022\u5e745\u670814\u65e5","format":false,"excerpt":"## \u30a8\u30e9\u30fc\u306e\u5185\u5bb9 TypeScript\u3067\u3001styled-components\u3092import\u3059\u308b\u3068\u3001\u2026","rel":"","context":"JavaScript","img":{"alt_text":"","src":"https:\/\/i0.wp.com\/akamist.com\/blog\/wp-content\/uploads\/2022\/01\/icon_typescript.png?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":5279,"url":"https:\/\/akamist.com\/blog\/archives\/5279","url_meta":{"origin":5249,"position":2},"title":"[MUI] @mui\u4ee5\u4e0b\u306e\u30d5\u30a1\u30a4\u30eb\u30a4\u30f3\u30dd\u30fc\u30c8\u3057\u3088\u3046\u3068\u3057\u305f\u3089TS2792\u30a8\u30e9\u30fc\u304c\u51fa\u308b","date":"2022\u5e741\u670827\u65e5","format":false,"excerpt":"## \u767a\u751f\u3057\u305f\u30a8\u30e9\u30fc React + TypeScript\u306e\u74b0\u5883\u3067\u3001MUI\u3092\u3057\u3088\u3046\u3068\u3057\u305f\u3068\u3053\u308d\u3001im\u2026","rel":"","context":"JavaScript","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":2248,"url":"https:\/\/akamist.com\/blog\/archives\/2248","url_meta":{"origin":5249,"position":3},"title":"[Angular]form\u306einvalid\u30d7\u30ed\u30d1\u30c6\u30a3\u4f7f\u7528\u6642\u306b\u300cCannot read property 'invalid' of undefined\u300d\u30a8\u30e9\u30fc\u304c\u767a\u751f","date":"2018\u5e743\u670825\u65e5","format":false,"excerpt":"## \u767a\u751f\u3057\u305f\u4e8b\u8c61 form\u306b\u8a2d\u7f6e\u3057\u305fsubmit\u30dc\u30bf\u30f3\u306edisabled\u5236\u5fa1\u306bForm\u306einval\u2026","rel":"","context":"Angular","img":{"alt_text":"","src":"https:\/\/i0.wp.com\/akamist.com\/blog\/wp-content\/uploads\/2018\/03\/icon_angular.png?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":5491,"url":"https:\/\/akamist.com\/blog\/archives\/5491","url_meta":{"origin":5249,"position":4},"title":"graphql-codegen\u3067\u30a8\u30e9\u30fcUnable to find template plugin matching typescript-operations\u304c\u51fa\u308b\u3068\u304d","date":"2022\u5e745\u67084\u65e5","format":false,"excerpt":"## \u30a8\u30e9\u30fc\u5185\u5bb9 `npm install @graphql-codegen\/cli`\u3068`.\/nod\u2026","rel":"","context":"\u672a\u5206\u985e","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":2236,"url":"https:\/\/akamist.com\/blog\/archives\/2236","url_meta":{"origin":5249,"position":5},"title":"[Anguler]ngModel\u3092\u4f7f\u7528\u6642\u306b\u3001\u30a8\u30e9\u30fc\u300cCan't bind to 'ngModel' since it isn't a known property of 'input'\u300d\u304c\u767a\u751f","date":"2018\u5e743\u670824\u65e5","format":false,"excerpt":"Anguler\u3067ngModel\u3092\u4f7f\u7528\u3057\u305f\u3068\u304d\u3001\u30d6\u30e9\u30a6\u30b6\u306econsole\u306b\u4e0b\u8a18\u306e\u30a8\u30e9\u30fc\u304c\u51fa\u308b\u5834\u5408\u304c\u3042\u308a\u2026","rel":"","context":"Angular","img":{"alt_text":"","src":"https:\/\/i0.wp.com\/akamist.com\/blog\/wp-content\/uploads\/2018\/03\/icon_angular.png?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/posts\/5249"}],"collection":[{"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/comments?post=5249"}],"version-history":[{"count":1,"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/posts\/5249\/revisions"}],"predecessor-version":[{"id":5252,"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/posts\/5249\/revisions\/5252"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/media\/5251"}],"wp:attachment":[{"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/media?parent=5249"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/categories?post=5249"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/akamist.com\/blog\/wp-json\/wp\/v2\/tags?post=5249"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}