{"id":915,"date":"2016-12-14T18:11:33","date_gmt":"2016-12-14T18:11:33","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/typescript\/?p=915"},"modified":"2019-02-20T10:45:57","modified_gmt":"2019-02-20T17:45:57","slug":"writing-dts-files-for-types","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/typescript\/writing-dts-files-for-types\/","title":{"rendered":"Writing Declaration Files for @types"},"content":{"rendered":"
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A while back<\/a> we talked about how TypeScript 2.0 made it easier to grab declaration files for your favorite library. Declaration files, if you’re not familiar, are just files that describe the shape of an existing JavaScript codebase to TypeScript. By using declaration files (also called .d.ts<\/code> files), you can avoid misusing libraries and get things like completions in your editor.<\/p>\n

As a recap of that previous blog post, if you’re using an npm package named foo-bar<\/code> and it doesn’t ship any .d.ts<\/code> files, you can just run<\/p>\n

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npm install -S @types\/foo-bar<\/pre>\n<\/div>\n
and things will just work from there.<\/p>\n
But you might have asked yourself things like “where do these ‘at-types’ packages come from?” or “how do I update the .d.ts<\/code> files I get from it?”. We’re going to try to answer those very questions.<\/p>\n
DefinitelyTyped<\/h2>\n
The simple answer to where our @types<\/code> packages come from is DefinitelyTyped<\/a>. DefinitelyTyped is just a simple repository on GitHub that hosts TypeScript declaration files for all your favorite packages. The project is community-driven, but supported by the TypeScript team as well. That means that anyone can help out or contribute new declarations at any time.<\/p>\n
Authoring New Declarations<\/h2>\n
Let’s say that we want to create declaration files for our favorite library. First, we’ll need to fork DefinitelyTyped<\/a>, clone your fork, and create a new branch.<\/p>\n
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git clone https:\/\/github.com\/YOUR_USERNAME_HERE\/DefinitelyTyped\ncd DefinitelyTyped\ngit checkout -b my-favorite-library<\/pre>\n<\/div>\n
Next, we can run an npm install<\/code> and create a new package using the new-package<\/code> npm script.<\/p>\n
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npm install\nnpm run new-package my-favorite-library<\/pre>\n<\/div>\n
For whatever library you use, my-favorite-library<\/code> should be replaced with the verbatim name<\/strong> that it was published with on npm.\nIf for some reason the package doesn’t exist in npm, mention this in the pull request you send later on.<\/p>\n
The new-package<\/code> script should create a new folder named my-favorite-library<\/code> with the following files:<\/p>\n