32054f1c31
* Forbid accessing const & let on globalThis It's just an error; you still get the type of the property. * Disallow access of blockscoped vars on globalThis Also change Array, Function, String, et al from `const` to `var` so that they remain accessible via `globalThis.String`. * Update baselines after lib.d.ts change Note especially the change in redefineArray, which is now allowed as long as you provide a type that is assignable to ArrayConstructor. * Remove blockscoped vars from typeof globalThis Unlike forbidding them, this removes the properties entirely. Unfortunately, this means that accessing these properties is only an error with noImplicitAny, and that error is quite confusing. Let's discuss our options. I see 3: 1. Forbid access of block-scoped vars as properties (in all flag settings), but leave them on the type. Simple to implement. 2. Remove block-scoped vars from the globalThis type. Has the bad error/flag behaviour described above, but simple to implement. 3. Remove block-scoped vars from the globalThis type. Also, forbid accessing them by executing another resolveName lookup for failed property accesses on globalThisSymbol. If the second lookup returns a blockscoped var, issue an error instead of falling back to the index signature. This seems too complex to me. * Update baselines * Better error for block-scoped usage on globalThis So that value-space references have as clear an error as type-space references. * Update fourslash tests * Fix semi-colon lint * Don't copy so much when filtering blockscoped vars
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.
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.
- 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
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.
# 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.
Usage
node built/local/tsc.js hello.ts
Roadmap
For details on our planned features and future direction please refer to our roadmap.