TypeScript 4.5 is due to reach the release candidate stage on November 2 and to be generally available on November 16. The beta is accessible via NuGet or NPM:
npm install typescript@betacode.
Also new in TypeScript 4.5:
- The release introduces an easy way to override a specific built-in
libto better support the
- To improve speed, a system-native implementation of the Node.js
realpathSyncfunction is now leveraged on all operating systems. Previously, it was limited to Linux. Now it has been adapted to OSes that are typically case-sensitve, like Windows and MacOS.
- Snippet completions are offered for JSX attributes.
- An ECMAScript proposal for checking whether an object has a private field is supported. Another ECMAScript proposal, for import assertions, also is supported. This is a syntax used by runtimes to ensure that an import has an expected format.
- Better editor support is offered for unresolved types.
- A utility type, the
Awaitedtype, is introduced for modeling operations like
asyncfunctions or the
Awaitedcan be useful for modeling existing APIs.
- Values that have template strings can be narrowed. Also, template strings are recognized as discriminants.
- A new
es2022, is supported, providing top-level
await, meaning developers can use
- Some tail-recursion elimination is performed on conditional types.
- Part of TypeScript 4.5 allows a
typemodifier on individual named imports.
Paul Krill is an editor at large at InfoWorld, whose coverage focuses on application development.
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