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368cdfd29a
* chore: failing test for const enums and isolatedModules
* fix: const enums + isolatedModules emit invalid code
In `isolatedModules` mode, the compiler does not inline const enums,
but also decides not to `import` them, leaving invalid code that
throws a `ReferenceError` at runtime.
This code:
```
import { SomeEnum } from './bar';
sink(SomeEnum.VALUE);
```
..should compile to either:
```
var { SomeEnum } = require('./bar');
sink(SomeEnum.VALUE);
```
..or (with const enum inlining):
```
sink(1 /* VALUE */);
```
..but actually compiles to:
```
sink(SomeEnum.VALUE);
```
..with no imports, which throws a ReferenceError at runtime.
---
The compiler has already realised that the symbol is a referenced const
enum, it just doesn't use this information when it comes to deciding
whether to emit an import. This commit additionally checks that
information, if we are compiling in isolatedModules mode.
---
In my opinion, this is not the correct fix, but it is the simplest. In
`isolatedModules` mode, `const enum` should probably be a compile error
(because there are no benefits and the complexity is high, and,
apparently, buggy). If not, the compiler should not be checking whether
something is a const enum, and should just be treating it as a regular
enum, and checking as if it was?
Fixes #40499.
* chore: extra test for type-only
* feat: explicitly ban --isolatedModules --preserveConstEnums false
* feat: isolatedModules implies preserveConstEnum
* Update src/compiler/diagnosticMessages.json
Co-authored-by: Andrew Branch <andrewbranch@users.noreply.github.com>
* chore: compiler test for argument incompatibility
* Add and fix test for namespace import of const enum
* Fix additional bug with reexport of const-enum-only module
Co-authored-by: Andrew Branch <andrewbranch@users.noreply.github.com>
Co-authored-by: Andrew Branch <andrew@wheream.io>
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.
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- Help each other in the TypeScript Community Discord.
- Join the #typescript discussion on Twitter.
- Contribute bug fixes.
- Read the archived 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 ci
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 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.