--- title: Type guards are easy but... | daily.dev description: is-kit is a TypeScript library that converts repetitive type guard checks into small, reusable, composable predicates. Instead of writing one-off type checks... canonical: https://daily.dev/posts/type-guards-are-easy-but--iwjgxsp4i twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Type guards are easy but... | daily.dev og:description: is-kit is a TypeScript library that converts repetitive type guard checks into small, reusable, composable predicates. Instead of writing one-off type checks... og:url: https://daily.dev/posts/type-guards-are-easy-but--iwjgxsp4i og:image: https://api.daily.dev/og/posts/IWJgXSp4i.png og:image:alt: Type guards are easy but... og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Type guards are easy but... **[nyaomaru](https://daily.dev/sources/graxwfjk0eop4zs3tdzdr)** · [@nyaomaru](https://daily.dev/nyaomaru) · 1 min read · 0 upvotes · 0 comments ## Summary is-kit is a TypeScript library that converts repetitive type guard checks into small, reusable, composable predicates. Instead of writing one-off type checks scattered across error handling, API responses, arrays, and literal values, developers can build modular guards and compose them together. ## Content Type guards are easy to write once. The problem starts when similar checks spread across error handling, API responses, arrays, and literal values. `is-kit` turns those one-off checks into small, reusable predicates that you can compose and pass around. Build small guards. Compose them. 😸 https://github.com/nyaomaru/is-kit --- Tags: [#typescript](https://daily.dev/tags/typescript), [#functional-programming](https://daily.dev/tags/functional-programming) [View this post on daily.dev](https://daily.dev/posts/type-guards-are-easy-but--iwjgxsp4i) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"DiscussionForumPosting","mainEntityOfPage":"https://daily.dev/posts/type-guards-are-easy-but--iwjgxsp4i","headline":"Type guards are easy but...","text":"is-kit is a TypeScript library that converts repetitive type guard checks into small, reusable, composable predicates. Instead of writing one-off type checks scattered across error handling, API responses, arrays, and literal values, developers can build modular guards and compose them together.","url":"https://daily.dev/posts/type-guards-are-easy-but--iwjgxsp4i","datePublished":"2026-08-06T14:45:50.088Z","dateModified":"2026-08-06T14:46:06.896Z","author":{"@type":"Person","name":"nyaomaru","url":"https://daily.dev/nyaomaru","image":"https://avatars.githubusercontent.com/u/90489696?v=4","interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"EndorseAction"},"userInteractionCount":280}},"interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"isPartOf":{"@type":"WebPage","url":"https://daily.dev/sources/graxwfjk0eop4zs3tdzdr","name":"nyaomaru"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"nyaomaru","item":"https://daily.dev/sources/graxwfjk0eop4zs3tdzdr"},{"@type":"ListItem","position":3,"name":"Type guards are easy but..."}]} ```