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Microsoft has released the TypeScript 5.0 beta version, which aims to simplify, speed up and reduce the size of TypeScript. The beta release incorporates new decorators standards that enable users to customize classes and their members in a reusable manner.

One of the key highlights of this beta release is the incorporation of new decorators standards that enable users to customize classes and their members in a reusable manner. Daniel Rosenwasser, program manager of TypeScript, wrote in a recent post on the Microsoft blog that these experimental decorators have been incredibly useful, but they modeled an older version of the decorators proposal and always required an opt-in compiler flag called --experimentalDecorators. Rosenwasser stated that developers who have been using “--experimentalDecorators” are already aware that, in the past, any attempt to utilize decorators in TypeScript without enabling this flag would result in an error message.

Rosenwasser described the long-standing oddities around enums in TypeScript and how the beta release of TypeScript 5.0 has cleaned up some of these problems while reducing the number of concepts needed to understand the various kinds of enums one can declare.

TypeScript is an open-source programming language and a superset of JavaScript, which means it builds upon and extends the functionality of JavaScript. It was developed and is maintained by Microsoft. 

The new decorators proposal in TypeScript 5.0 allows developers to write cleaner and more maintainable code with the added benefit of being able to customize classes and their members in a reusable manner. While the new decorators proposal is incompatible with --emitDecoratorMetadata and does not support parameter decoration, Microsoft anticipates that future ECMAScript proposals may be able to address these limitations.

In addition to the new decorators proposal, TypeScript 5.0 includes several improvements such as more precise type-checking for parameter decorators in constructors, const annotations, and the ability to allow the extends field to take multiple entries. It also includes a new module resolution option in TS, performance enhancements, and exhaustive switch/case completions.

TypeScript targets ECMAScript 2018, which means that Node.js users must have a minimum version of Node.js 10.

To start using the beta version, users can obtain it through NuGet or use the npm command:

npm install typescript@beta