TypeScript 4.7 adds ESM support in Node.js

TypeScript 4.7, now in a launch candidate (RC) stage, provides ECMAScript module (ESM) assist for Node.js 16 as perfectly as a multitude of coding enhancements.

The RC was unveiled May perhaps 11. TypeScript 4.7 is the most current planned version of Microsoft’s strongly typed JavaScript. The TypeScript 4.7 beta released April 8 backed ECMAScript module guidance in Node.js 12, one thing that had been planned for TypeScript 4.5 late final yr but was delayed.

On the other hand, for the reason that Node.js 12 is no more time supported, TypeScript’s builders have started off the secure goal at Node.js 16, which really should give more recent ES module features these as pattern trailers even though also defaulting TypeScript to a larger focus on that supports top rated-degree await.

Nightly-only aid for ECMAScript modules in Node.js was rolled out in the TypeScript 4.5 timeframe. These modules enable reuse of code via packaging. Implementing this assist has been tough due to the fact Node.js was crafted on a distinctive module system, CommonJS. TypeScript 4.7 provides this operation with two module configurations, node12 and nodenext. Comments on this capacity is sought and can be supplied on GitHub.

TypeScript 4.7 is owing to turn out to be normally obtainable on May possibly 24. The RC can be accessed through NuGet or NPM:

npm put in typescript@rc

Other capabilities in TypeScript 4.7 include:

  • To manage module detection, TypeScript 4.7 introduces the solution moduleDetection.
  • A moduleSuffixes option is supported to customise lookup of module specifiers.
  • With control flow analysis for computer attributes, TypeScript analyzes the type of computed properties and narrows them correctly.
  • TypeScript now can execute a lot more granular inferences from features with objects and arrays. This allows varieties of these features to persistently move in a left-to-proper method, just like for basic arguments.
  • Functions and constructors can be fed form arguments immediately.
  • Builders can explicitly specify variance on form parameters.
  • Arrange Imports is done in a team-mindful method.
  • Snippet completions are presented for object literal approaches.
  • A readonly tuple now will take care of its length assets as readonly. This is a breaking change.
  • A preview editor command is featured for Go to Resource Definition.
  • In an additional breaking change, when producing a …spread in JSX, TypeScript now enforces stricter checks that the presented variety is really an item. As a end result, values with the varieties unfamiliar and never ever, and, extra almost never, null and undefined, no for a longer period can be distribute into JSX things.

Next the beta, TypeScript’s builders uncovered that a typeof capability on #personal fields, which had been planned for the release, experienced problems with API compatibility. The workforce also started doubting whether typeof this.#somePrivate composes well on declaration emit. As a outcome, this capacity has been remaining out of TypeScript 4.7.

Predecessor TypeScript 4.6, centering on abilities these types of as ECMAScript 2022 aid and recursion checks, was released February 28.

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