TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
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Join the chat at https://gitter.im/Microsoft/TypeScript

TypeScript is a language for application-scale JavaScript. TypeScript adds optional types, classes, and modules to JavaScript. TypeScript supports tools for large-scale JavaScript applications for any browser, for any host, on any OS. TypeScript compiles to readable, standards-based JavaScript. Try it out at the playground, and stay up to date via our blog and Twitter account.


For the latest stable version:

npm install -g typescript

For our nightly builds:

npm install -g typescript@next


There are many ways to contribute to TypeScript.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.



In order to build the TypeScript compiler, ensure that you have Git and Node.js installed.

Clone a copy of the repo:

git clone https://github.com/Microsoft/TypeScript.git

Change to the TypeScript directory:

cd TypeScript

Install Gulp tools and dev dependencies:

npm install -g gulp
npm install

Use one of the following to build and test:

gulp local            # Build the compiler into built/local 
gulp clean            # Delete the built compiler 
gulp LKG              # Replace the last known good with the built one.
                      # Bootstrapping step to be executed when the built compiler reaches a stable state.
gulp tests            # Build the test infrastructure using the built compiler. 
gulp runtests         # Run tests using the built compiler and test infrastructure. 
                      # You can override the host or specify a test for this command. 
                      # Use host=<hostName> or tests=<testPath>. 
gulp runtests-browser # Runs the tests using the built run.js file. Syntax is gulp runtests. Optional
                        parameters 'host=', 'tests=[regex], reporter=[list|spec|json|<more>]'.
gulp baseline-accept  # This replaces the baseline test results with the results obtained from gulp runtests.
gulp lint             # Runs tslint on the TypeScript source.
gulp help             # List the above commands. 


node built/local/tsc.js hello.ts


For details on our planned features and future direction please refer to our roadmap.