Declaration files (.d.ts files) are a fundamental part of using existing JavaScript libraries in TypeScript, but getting them has always been a place where we’ve known there was room for improvement. As we get closer to TypeScript 2.0, we’re very excited to show off a sneak peak of our plan to simplify things. Getting type declarations in TypeScript 2.0 will require no tools apart from npm.
As an example, getting the declarations for a library like lodash will be just an npm command away:
npm install --save @types/lodash
From there you’ll be able to use lodash in your TypeScript code with no fuss. This works for both modules and global code.
For example, once you’ve npm install-ed your type declarations, then you can use imports and write
import * as _ from "lodash"; _.padStart("Hello TypeScript!", 20, " ");
or if you’re not using modules, you can just use the global variable _ if you have a tsconfig.json around.
_.padStart("Hello TypeScript!", 20, " ");
Looking for more than just lodash? Well, we’re also making it extremely easy to figure out which packages have the type declarations you need. We now have a type search at https://aka.ms/types where you can find the package for your favorite library.
Best of all, this all works today with our nightly builds. Just run npm install -g typescript@next, and give it a shot. This is all you need to know to start experiencing the future of type acquisition.
We’d love to hear your thoughts, so if you’d like to give us your feedback or just understand the specifics, head on over to GitHub to read more or leave a comment.
Notes and Acknowledgements
For those wondering, DefinitelyTyped will still be the place to author new declaration files. We’ll soon be providing a greatly expanded set of documentation aimed at .d.ts authors in the near future. Tools like Typings and tsd will continue to work, and we’ll be working alongside those communities to ensure a smooth transition.
We also owe a great thanks to those who helped guide us in this direction. Specifically, Blake Embrey, the maintainer and creator of Typings, has worked closely with us during this entire process and given us valuable feedback. In addition to this, Boris Yankov, founder of DefinitelyTyped, and Diullei Gomes and Bart van der Schoor, maintainers of tsd, have helped lay the foundation of these efforts.
Lastly, we’ll mention that this is still a work in progress. Editor support is currently limited to Visual Studio Code and our Sublime plugins, with Visual Studio support on the way. We absolutely value all the feedback we can get, so try out our nightly builds and let us know what the new experience is like!
How will versioning work for npm-based types? Will the @types/ based module require the right matching version ranges so the API’s match? If I upgrade lodash to a new major version will I get an error if there’s no matching @types/ entry for that version yet?
Admittedly, the existing versioning story isn’t great either (especially if you need to stay downlevel of ‘last stable release’), but if we’re going to have a more ‘TypeScript-native’ solution coming, I hope it’s a good time to tackle that.
In an ideal world the .d.ts files exist in the same npm package as the source (lodash or whatever) so the versioning story is simple – just use the types in that package – but until then, it’d be great to have a good versioning answer. 🙂
The major and minor version number of the types package will match the version of the underlying package, with the patch version tracking the version of the definition file.
Since most libraries are backward-compatible, we won’t issue any warning if e.g. you get the 3.x version of types for the 4.x version of a package.
OMG!
> Since most libraries are backward-compatible, we won’t issue any warning if e.g. you get the 3.x version of types for the 4.x version of a package.
You might wanna check http://semver.org/:
>Given a version number MAJOR.MINOR.PATCH, increment the:
>
> MAJOR version when you make incompatible API changes,
> …
i. e. Changing the major version from 3.x to 4.x means *precisely* that breaking changes have been introduced.
i. e. *Not* backward-compatible.
OMG, OMG! 🙂
OMG indeed! I really really hope that this solution doesn’t have architectural flaws that would exclude implementing semver.
But the comment from James reflects precisely my thoughts:
“In an ideal world the .d.ts files exist in the same npm package as the source (lodash or whatever) so the versioning story is simple – just use the types in that package”
Please have semver in mind!
I’m not sure if it’s already widely known, but I think it would also be nice to add short blog post about how library authors can include types definitions within the same package using the typings property in the package.json. If they’re using tsc to generate .d.ts from the source .ts files then the type definitions could more easily be deployed instead of having to publish it in different @types scoped package.
+1. Also the same approach can be used if library uses ES6/ES7 with flow types – then also .d.ts can be generated directly from the source and distributed with the package.
Awesome that I need to have Node installed in order to build a client application in visual studio.
Microsoft is moving towards using the right tool for the job as opposed to making everything revolve around a Microsoft ecosystem. They’re going where the developers are going – and that’s ultimately good for us.
There will probably be tooling available soon that will allow you to install typings from within Visual Studio. However, I encourage you to read more about using npm and Node to enhance your development experience.
You’ve needed to have Node installed to build browser applications with any IDE for a long time. Or at least, if you haven’t had Node installed, you’ve been doing it wrong.
This is awesome and frankly is one of the reasons I haven’t pushed TypeScript to beginners as much. I could explain why you’d want to use TypeScript and beginners seemed open to it, but ultimately the toolchain made it prohibitive. Exciting work gang.
Quite literally drooling… This is awesome.
I don’t use or want to use NPM, should I move to a deserted island now?
No need to move anywhere 🙂
You can still use your current setup to acquire and manage declaration files. If the compiler can find them today, it should continue to work in the new setup.
Why don’t you want to use NPM?
It’s called tool-o-phobic! haha.. 🙂
Because I use jspm
Using jspm doesn’t conflict with using npm to get types. In fact to have jspm you had to have npm installed and additionally jspm uses npm internally so you should be set to use npm to get types when this change arrives.
But…this is for what the “typings” community called “ambient” type definitions and now call “global”. One of the purposes of typings is to use the official definitions file that every library author should now include…at least if they want to work well with Angular 2. How does this “npm @typings” scope solve that problem? Or is there another facility in the TS 2.0 tsc to handle official .d.ts files gracefully?
For packages that include their own declaration files, e.g. Angular2, or TypeScript there is nothing that needs to be done. The TS 2.0 compiler will pick up the definition file from the package location like it does today.
These changes are mainly aimed about packages that do not ship their own declaration files. The proposal as outlined above allows for using npm as the main engine, handles versioning, and dependency, as well as conflicting versions of declaration files (manifest as duplicate definition errors) that users have reported in the past.
It looks like the type modules are auto-generated from the DefinitelyTyped repo. What is the process for updating npm with the new typings if I submit an accepted PR to DefinitelyTyped?
We have an automated publisher that synchronizes the package based on any updates to DefinitelyTyped. It’s a work in progress, but see https://github.com/Microsoft/types-publisher.
Awesome.
Will any resources be provided to DefinitelyTyped to get working on those 500 PRs?
Thanks!
I’m seeing an outdated react-router.d.ts on npm. What could be the problem?
The DefinitelyTyped github project has a “master” branch, and a “types-2.0” branch.
What is the correct process to make a change to a .d.ts project ?
1]
First create the fix as a PR in the “master” branch and then duplicate the code changes in a new PR on the”types-2.0″ branch ?
2]
Or create a PR in the “master” branch and also create a PR on the “types-2.0” branch which does a merge ?
I just found this: https://github.com/Microsoft/types-publisher/issues/164#issuecomment-253336439
Would it be possible to autosync NuGet packages ? Simialr way you’ll arrange it for NPM ? In VS we consume d.ts this way (where possible), but it is now not consistent – sometimes in REPO is newer version or a d.ts, which does not exist in NuGet.
I honestly don’t understand the article completely, what is the delimitation or difference between the ‘tsd’ tool (now ‘typings’) and the new ‘npm install’ approach?
Firstly there is DefinitelyTyped which is just a catalog of typings that others have made. TSD is a command line tool to install typings into your project from the DefinitelyTyped repo. Typings is another command line too that can install typings from DefinitelyTyped, GitHub, npm, etc, and can create .d.ts files from your own TypeScript code. The `npm install` approach will let you cut out the need for those other two tools if all you’re doing is installing typings from DefinitelyTyped. Microsoft will automatically publish typings from the DefinitelyTyped repo to npm so that you can put any typings you need into your package.json. The v2 TypeScript compiler will know how to find them once they’re in your node_modules folder.
Well, that makes things much clearer for me and I’m looking forward for that easier way of typing (pun intended).
Thank you, Sir 🙂
Sounds good but I’m a bit confused. Will this generate the typings by running the .js files through the Typescript Compiler? Does it pull them from DefinitelyTyped?
This will publish the typings from the DefinitelyTyped repo to npm. The TypeScript compiler will know how to find the typings once you’ve installed them into your node_modules folder.
This is a real breakthrough, thanks!
Nit with the lodash example:
`npm install –save @types/lodash`
should probably be `–save-dev` rather than `–save`, since this dependency is purely a development/build step thing.
No, You can use it in browser as well. `–save` was probably chosen because browsers might be the place where lodash is most often used 😉
You are talking about lodash, I’m talking about @types/lodash. You only need the types for building, not running.
I guess because you could also load typescript to browser and compile it here.
I’m not that frontend guy so these question might be stupid:
Ok, so what is the recommended solution if I have my own Javascript dependencies that are in different git repo and I include them in my project using bower? I want to move this packages to Typescript.
Should I rewrite them to Typescript and generate one .js file and one .d.ts file and include those files in bower package?
Should I include one generated .js file in bower and publish typing to npm with this “@types/” stuff and include js as bower dependency and types as npm dependency?
Should I just have .ts files in bower package?
Other question: I used “typings” very briefly but from what I remember it was possible to get “module” or “global” typings, so for example you could just include module typing for jquery so i must be used as module not a global “$” variable. Is it possible with this “@types/” stuff in npm? I might be wrong about this.
This is indeed possible with the @types stuff. The compiler will automatically find global declarations from the first @types folder, and if you you need the compiler to search a little farther, there will be a ‘types’ property in ‘tsconfig.json’ to specify that you need a specific set of files, which would look something like this:
{
"compilerOptions": {
"types": ["jasmine", "jquery"]
}
@daniel
but how should I actually install jquery typings so there would NOT be globally defined $ variable. I want to force programmers to not use this global variable, so they would always import “jquery” module?
So long as your files are all modules, you will get an error for using the global variable. That might be handled by a linter, or it might be handled by us: https://github.com/Microsoft/TypeScript/issues/9082.
Awesome stuff, that was the only thing which always bothered me about TS. Keep up the good work!
Awesome, thanks!
It would be nicer if these could be globally installed or if my ide was just smart enough to grab the type files for each library I have an import for. At minimum this post should say –save-dev since they are development dependencies.
Doesn’t the current compiler already do this with “moduleResolution: node”?
What about jspm? A solution is needed there.
With JSPM you’ll be able to use map paths to configure how the compiler does module resolution. See https://github.com/Microsoft/TypeScript/issues/5039
Glee! 🙂
Great work!
If i want to use types for react-router i need history.d.ts as well, otherwise it won’t compile (https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/react-router), how does it work with the new approach?
This sounds great!
One issue I’ve run into that I don’t see addressed by this approach is version tracking of the TypeScript language. Right now in DefinitelyTyped there seems to be no way to determine what version of TypeScript is used in a declaration file, and so whether it can be expected to work in my codebase. The file could use language features not supported by my version of the compiler, or rely on types from an outdated lib.d.ts that are no longer present in a more current one I may be using.
Versioning through npm solves the problem of tracking the version of the annotated library, but I don’t find the language version dimension addressed. Any thoughts?
Hey Johannes, I believe the plan is to tag releases with the minimum TypeScript version that is expected. We’ll have more details as we go along.
I agree with Johannes that this is an important consideration. There should also be a way to publish multiple definition files for a library so you can use newer features as they are released. For instance I am using Inquirer in a project and it has typed to any in places where a union type ( including string literal type ) would be the appropriate choice. Then there is yeoman-generator that is typing a property to {} instead of an indexed type.
Perhaps it is possible and I have not found details on it.
Your thoughts would be appreciated.
I take that back on Inquirer ( as any allows for extensibility ) but the point remains.
How will it work with private packages? (private npm)
Same question… Haven’t been able to find anything on this.
I need more information of “types-metadata.json” spec for publish my declaration files.
How can I find that?
Did you ever find out about types-metadata.json?
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I’ve used typescript to build a few projects and I am really happy that Microsoft will provide an official way for developers to get the declaration files. I remember when I started using typescript, I spent a few days on just comparing the tsd and typings.
When I use the typescript, another time consuming thing is to find a good typescript declaration file. Most of javascript libraries do not provide the official typescript declaration file and it relies the community to provide it. But sometimes there are multiple d.ts files provided by different persons from different place. So it is really time-consuming to find out which one is the best. Can Typescript provide a service to let developers rate and comment the d.ts files, so other developers can check the rating and the comment to easily pick the right one. This idea is similar to the Wine application database https://appdb.winehq.org/. If all d.ts files’ rating are not good enough, developers can then just use “declare var XXX” to ignore the type.
Has anyone managed to get it to work with Webpack and ts-loader?
Most ( if not all ) of the definition files from definitelytyped pollute the global namespace by declaring their export var outside the module declaration… meaning that TSC doesn’t catch missing imports when compiling in AMD mode.
— BAD non module —
var xx: yy;
declare module ‘zz’ {
export = xx;
}
— GOOD module —
declare module ‘zz’ {
var xx: yy;
export = xx;
}
I would like better tooling support for generating d.ts files in the editor on a per file basis, instead of trying to generate all files at compile time. Makes it easier to version your definition files for source control
Is this supported in the 2.0 beta? I don’t see any mention of it in the blog post.
i an import as like below.
import “@types/es6-promise”;
But it throws error as Exported external package typings file ‘d:/typescript/ts-base-library/node_modules/@types/es6-promise/index.d.ts’ is not a module. Please contact the package author to update the package definition.
also i have tried with jasmine, jasmine-ajax. same error thrown, is am anything do wrong? or missed anything?
is this supposed to work in the current TS 2.0 Beta?
d.ts installed through npm @types don’t seem to be picked up by the compiler:
https://stackoverflow.com/questions/38347734/typescript-2-0-types-not-automatically-referenced
I still believe that TypeScript-aware JavaScript libraries should come along with their .d.ts files right in their packages at the ready.
No second request, no versioning check would be required, and both, DefinitelyTyped as well as the new import feature would become obsolete over time.
Agreed! If you install @types/lodash you get some file from DefinitelyTyped. Why should I use that when lodash itself provides a d.ts file specific to that very version of lodash?
Thanks for this; however, I’m facing one issue. I cannot run this in command-line
$ tsc gulpfile.ts node_modules/@types/**/*.ts
While working with tsd, we could do
$ tsd install gulp –save
…and the /// would be saved in the “typings/tsd.d.ts” file – a single file where all references are stored and then we could
$ tsc gulpfile.ts typings/tsd.d.ts
…this would compile gulpfile.ts into gulpfile.js. How can we deal with such a thing in node_modules/@types/**/*.ts? Is there a way to get references to all the files in one single file?
It took me quite a bit to figure out why this didn’t work with Visual Studio Code: http://ilikekillnerds.com/2016/07/getting-visual-studio-code-work-next-versions-typescript/
>> Editor support is currently limited to Visual Studio Code and our Sublime plugins, with Visual Studio support on the way.
It is frustrating that the tool my company paid money for is not supported, but Microsoft’s free tool is.
Why do we pay for it if it gets second class support?
It has been a few months, Any update on Visual Studio support for this?
Will this be in in time for 2.0 rtm?
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Getting dozens of these errors now.
…../@angular/common/src/directives/ng_class.d.ts(81,34): error TS2304: Cannot find name ‘Set’.
…./@angular/common/src/pipes/async_pipe.d.ts(41,38): error TS2304: Cannot find name ‘Promise’.
The whole typings thing is a nightmare for newbies (10 years making website)
@Gary, did you find any solution to the problem? I am also having error like
…/shared/backup.test.ts (5,1): error TS2304: Cannot find name ‘describe’.
When I just use `tsc`, everything compiles fine. I get this error with webpack (using ts-loader).
Hi guys,
Looking for a bit of advice/clarification on this feature and my current situation. Basically, I have a private NPM repo (using Sinopia) that I am using to publish packages that can be shared throughout the company. Will this feature allow me to publish .d.ts files automatically with my .js library files when I type “npm publish”? Or do I need to publish a separate “@types\mypackage” package?
I’ve tried setting my “types” property to point to my .d.ts files in package.json, but this doesn’t seem to do anything. Is this supposed to automatically publish my .d.ts files so that when I do “npm install mypackage” the .d.ts files get automatically put in “node_modules\@types\mypackage”? Or am I misunderstanding the feature/use case completely?
Any help/advice is appreciated, thanks.
Packages in the ‘@types’ scope are only to serve packages that *don’t* come with their own .d.ts files.
If you’re already publishing .d.ts files with your package, then you don’t have to worry about this (unless ‘myPackage’ has dependencies on packages that don’t come with declaration files, in which case it should itself rely on their @types packages).
Thanks Daniel. I see how this feature works now. It’s just that I’m having trouble importing my own npm modules using just “import { types } from “my_node_module_name” – my typescript won’t compile as it can’t find this module. May be a little off-topic, but if you’re happy to give advice – isn’t my compiler supposed to be able to resolve types by just supplying the npm module name?
Why exactly are we going back to DT? That repository is a mess. It has nothing but good intentions – but there was a reason why the community started moving away from it to other arguably more polished solutions, like typings. Most definitions now in there are way outdated, compared to, say, those in the typings registry. Almost 1K open issues and nearly 200 PRs, with an unmanageable growing file tree with no clear structure.
Isn’t `npm i @types/xxx` basically what `tsd install` was? What’s to gain? Removing the need for a another tool? We use so many of them just to build our TS projects, that I don’t really see a major benefit here.
How would one go about installing the *.d.ts files for node itself?
Well, you could use @type/node, but that would give you the outdated DefinitelyTyped definitions. If you use Typings, you can do `typings install –save env~node –global` to get a more updated version. I completely agree with the above comment that DefinitelyTyped definitions _aren’t_ the way to go for the source for what gets into NPM.
I found new DefinitelyTyped package have adopt this feature to provide global variables. for example:@types/bluebird-global.. it does work if install package local… but if install it as global package..(npm install –save @types/bluebird-global
) the module resolution don’t work. is it possible to resolve global package by ts compiler?
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When I use let map = new L.Map(‘map’, {
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zoom: 12,
});
it gives me error “Property ‘Map’ does not exist on typ
e ‘typeof L’
Please help
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It’s been 1.5 years- there seems to still be no VS support whatsoever for getting TS definition files. I don’t want to use command line Node tools. *That’s the entire reason I use an IDE in the first place, so I don’t have to use the command line*
Are there any plans to fix the ever present mess of trying to get definition files?