Typescript satisfies and as const Dec 20, 2022 · TypeScript 4.

Typescript satisfies and as const. 9. Jul 6, 2023 · Use satisfies operator with const assertions to get the best of type inference, type safety, and immutability. Jan 14, 2023 · When you use as const on an array, typescript thinks of it as readonly. I'd like to add that satisfies allows TypeScript to infer the "narrower" type based on the actual value assigned while explicit type declaration will ignore the value and may result in type "widening" if your declared type is wider than the value (object literal in this case). So it seems like we should always prefer to use Using the satisfies keyword is one of four ways to make type assignments in TypeScript. . May 5, 2023 · The TypeScript satisfies operator is a new and better approach to type-safe configuration in TypeScript released in TypeScript v4. It is a new and effective way to ensure type safety in TypeScript. Jul 10, 2023 · The TypeScript satisfies operator checks if a given type satisfies a specific condition or interface. May 10, 2025 · This article explores two TypeScript features - as const assertions and the newer satisfies operator - that enable developers to enforce configuration integrity at compile-time without incurring runtime costs, making your code safer and easier to maintain. 9 から、 satisfies operator が使えるようになりました。従来の as const と組み合わせ、型チェックと widening 防止を同時に行えます。筆者的には、"顧客が本当に必要だったもの"です。 本記事では satisfies とは何か？ as const とは何か？ 2つを組合わせるとどのようなメリットがあるのか？ に Jun 4, 2023 · 现在，随着 TS 4. In this blog post, we examine how exactly it works and where it’s useful. Thanks! That's exactly what I was looking for. Nov 14, 2022 · How TypeScript's new `satisfies` operator brings the best of type annotations and default type inference. This blog post explores the satisfies keyword, outlines the problems with overreliance on as, and compares the two to help you make informed decisions in your TypeScript projects. Learn how to improve type safety, preserve literal types, and catch errors at compile time. 9 The satisfies Operator TypeScript developers are often faced with a dilemma: we want to ensure that some expression matches some type, but also want to keep the most specific type of that expression for inference purposes. Dec 20, 2022 · TypeScript 4. May 15, 2025 · In TypeScript, the satisfies operator is a safer, more precise alternative to as when you want to ensure a value conforms to a type without losing type inference. Feb 18, 2024 · それでは困る場合にas const とsatisfiesを組み合わせます。 as const と satisfiesの組み合わせ 2つを組み合わせるとさらに強力になり、satisfiesによる型チェックと、as const によるwideningの抑制ができるようになります。 Feb 25, 2025 · Master TypeScript's satisfies operator with practical examples. For example: Feb 8, 2025 · TypeScript’s satisfies operator lets us check the type of a value (mostly) without influencing it. Using satisfies, as const, and arrays together can be a little tricky. Jun 18, 2024 · Great comparison to explicit type declaration (const foo: Example). Let's take an example where we have a navigation menu that consists of elements with a title, an optional URL, and an optional array of nested navigation elements under the children property. Jun 24, 2025 · Understand the difference between satisfies and as operators in TypeScript. Learn when to use each for safer, type-safe, and more maintainable code. 9 introduced the new satisfies keyword, which is extremely handy for most configuration-related tasks in TypeScript. Essential guide for TypeScript developers. Jan 17, 2023 · Typescript 4. There is no need to type-check {name: "test"} as const because Typescript uses structural equality meaning aslong as {name: "test"} as const is the same structure of MyType they will be equal and therefore the same. But when should you use it? Feb 24, 2024 · A Deep Dive into the satisfies operator in Typescript We take a look at the satisfies Typescript operator and how to use it, when to use it and why you should use it instead of Type annotations and typer assertions. 9 的发布，我发现了在 TypeScript 中有了一种新的、更好的方式来做类型安全校验。它就是 satisfies , 先给大家上一道小菜先睹为快： 为什么是 satisfie TypeScript 4. So, you need to make your satisfies type readonly. atugcj avcpmfp yzuwk pcg qbpg jjk sbftfu bbiul xey luz