TypeScript

TypeScript is a language for application-scale JavaScript. TypeScript adds optional types to JavaScript that support 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.

Find others who are using TypeScript at our community page.

# Installing

For the latest stable version:

npm install -g typescript

For our nightly builds:

npm install -g typescript@next

# Contribute

There are many ways to contribute to TypeScript.

- Submit bugs and help us verify fixes as they are checked in.
- Review the source code changes.
- Engage with other TypeScript users and developers on StackOverflow.
- Help each other in the TypeScript Community Discord.
- Join the #typescript discussion on Twitter.
- Contribute bug fixes.
- Read the language specification (docx, pdf, md).

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.

# Documentation

- TypeScript in 5 minutes
- Programming handbook
- Language specification
- Homepage

# Building

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.
# Some low-value tests are skipped when not on a CI machine - you can use the
# --skipPercent=0 command to override this behavior and run all tests locally.
# You can override the specific suite runner used or specify a test for this command.
# Use --tests=<testPath> for a specific test and/or --runner=<runnerName> for a specific suite.
# Valid runners include conformance, compiler, fourslash, project, user, and docker
# The user and docker runners are extended test suite runners - the user runner
# works on disk in the tests/cases/user directory, while the docker runner works in containers.
# You'll need to have the docker executable in your system path for the docker runner to work.
gulp runtests-parallel # Like runtests, but split across multiple threads. Uses a number of threads equal to the system
# core count by default. Use --workers=<number> to adjust this.
gulp baseline-accept # This replaces the baseline test results with the results obtained from gulp runtests.
gulp lint # Runs eslint on the TypeScript source.
gulp help # List the above commands.

# Usage

node built/local/tsc.js hello.ts

# Roadmap

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