TypeScript (TS) is a superset of JavaScript (JS), created at Microsoft in response to frustration developing large-scale applictions in JS. In a large JS project, knowing what properties your own objects have, what arguments your functions take (and what type they need to be) can become difficult. Similarly, since there is no ability to intelligently inspect JS code, when you include a package (like from npm), you have to keep the documentation up so you know what methods are available and what arguments they take. TS solves these issues. It is currently an open-source project hosted on Github. It supports tools for any browser as well as Node, for any host, on any OS. TTS compiles to readable, standards-based JavaScript.

TS adds a flexible type system to JS, in addition to interfaces (custom types) and modifying the syntax of some ECMAScript features such as classes. Types are optional and flexible (for example, you can specify an argument is a string OR a number). Types allow tooling available in most code editors that improve the development experience such as code completion and method detection, both in your own code and in packages you use. It supports many upcoming ECMASCript features (such as async/await). TS can be written in OO or functional styles. It is compatible with all existing JS packages. TS transpiles to clean, readable JS.

Try it out at the playground, and stay up to date via the Typescript blog and Twitter account.

Help us explain this better! File a GitHub issue at https://github.com/exercism/typescript/issues if you have suggestions, or submit a patch with improvements to the https://github.com/exercism/typescript/blob/master/docs/ABOUT.md file.

Try It!

If you've downloaded the command-line client and have TypeScript installed on your machine, then go ahead and fetch the first problem.

exercism fetch typescript

In order to be able to submit your solution, you'll need to configure the client with your Exercism API key.

exercism configure --key=YOUR_EXERCISM_KEY

When you've written a solution, submit it to the site. You'll have to configure the command-line client with your exercism API key before you can submit.

exercism submit PATH_TO_FILE