type-fest VS DefinitelyTyped

Related: https://github.com/sindresorhus/type-fest/blob/main/source/o...

Typescript doesn’t natively provide an Opaque type that we can use to define a string that has already been localized. If the data looks like a string, Typescript will consider it a string. We can however use utility types that simulate opaque types, like the Opaque definition in type-fest:

With these powerful features, you can create dynamic and expressive types. One last thing I want to mention before moving on, is that you can install libraries with which you can add more types to your project like type-fest or utility-types. These libraries contain a lot of useful types that you can use in your project.

Also, it’s not as restrictive as mutability tools — if you know what you are doing and want to ignore this limitation for a particular case, you can apply the -readonly modifier or the Writeable type from type-fest or ts-essentials.

Remember you can derive one type from another type so you can make sure they don't diverge. SetOptional type util

Some folks have built whole SQL databases and DSL compilers in the TS type system. These tend to be toy projects with disclaimers not to use them. But the type system being Turing complete[0] (for better or worse), pretty much whatever you can imagine. This project[1] is one I actually return to frequently for practical ideas.

0: https://github.com/microsoft/TypeScript/issues/14833

1: https://github.com/sindresorhus/type-fest

Have a look at SetRequired and SetOptional in type-fest

Try the Exact method provided by Type Fest, looks like it does what you're looking for

This is a fairly common scenario and available via libraries like type-fest or implementable with a couple lines of code.

Prior to React 18, it used to include an implicit children prop, making it suitable for components expected to have children. For a long time, though, the implicit children prop type has been removed according to React 18's type changes.

Additionally, because TypeScript has a well established and widely used install-base, there are already many different definition files in the wild for supporting non-TypeScript supporting projects. One of the more extensive collections of these typings lives at the DefinitelyTyped repository, which publishes the package's community typings under the package names @types/your-package-name (where your-package-name is the name of the project you're looking for typings of) that you can look for on your package manager.

View on GitHub

Firefox maintain a library for unified extension API https://github.com/mozilla/webextension-polyfill

Their type definition for HAR request isn't exported https://github.com/DefinitelyTyped/DefinitelyTyped/blob/mast...

type NumberOrString = number | string; type Status = "idle" | "loading" | "success" | "failure" // React useState, can receive a value or a function as parameter to serve as initial value. // https://github.com/DefinitelyTyped/DefinitelyTyped/blob/a03856975a17eba524739676affbf70ac4078176/types/react/v17/index.d.ts#L920 function useState(initialState: S | (() => S)): [S, Dispatch>];

The TypeScript pull request was merged, so Sebastian (who helps maintain the React type definitions) exercised new powers in this pull request to the DefinitelyTyped repository for the React type definitions. At the time of writing, this pull request is still open, but once merged and shipped the React community we will feel its benefits.

there is an open issue: https://github.com/DefinitelyTyped/DefinitelyTyped/issues/61616

Relatively infrequently. Normally, if an npm package is popular and doesn’t have its own types, there will be a community provided types declaration file available from https://github.com/DefinitelyTyped/DefinitelyTyped