TypeScript 3.6 is on schedule with a few breaking changes

Just in time as announced in the release of the beta version at the end of July, Microsoft is now reviving version 3.6 of the JavaScript superset TypeScript. Compared to the beta already listed as a feature complete, only further bugfixes and performance improvements have been added – also some breaking changes have been implemented. Among the new features of TypeScript 3.6 are more stringent checking for iterator and generator functions, a more precise array spread and a clearer handling when working with Promises.

With the change to TypeScript 3.6, developers have to consider different breaking changes. As part of an update to the Document Object Model (DOM), Microsoft has a number of declarations in lib.dom.d.ts changed or even removed. Instead of GlobalFetch is now WindowOrWorkerGlobalScope to use. webgl or webgl2 replace the experimental-webgl-Context. window is no longer than Type Window defined, but as a type Window & typeof globalThis,

In adaptation to the ECMAScript specification are class declarations with methods called constructor now constructor-Functions, whether they are with identifier– or stringNames were declared.

class C {
"constructor"() {
console.log("I am the constructor now.");

In addition, the escape sequences previously allowed in keywords are no longer used, and in JavaScript files TypeScript uses only the immediately preceding JSDoc comments when searching for declared types. The usual merge of JSDoc comments in earlier versions no longer occurs.

In the new TypeScript version Microsoft already has in beta Iterator and IteratorResult around different type parameters and the new one GeneratorType to allow developers to specify the yield and return type as well as specify which type next can accept. With for-of loops and array spreads for ECMAScript versions prior to ES2015, developers can now use the helper __spreadArrays, which should be more specific. Some enhancements to the Promise user experience are designed to help users work with asynchronous data. The previous use of an API, which is based on Promises, apparently gave rise to frequent confusion.

A complete overview of all the new features in TypeScript 3.6 provides the Blog post to release the release, References to the further improvements in the JavaScript Superset planned for the second half of the year can be found in the Roadmap on GitHub,


. (TagsToTranslate) JavaScript (t) programming (t) Type Script (t) Web development