Babel.js 7.4 comes with upgrades: TypeScript 3.4, core-js @ 3 and more


Babel 7.4 is an update to the JavaScript compiler that includes some upgrades and support for new proposals. Babel.js 7.4 supports, among other things, the latest TypeScript version, parentheses in the code and more.

Babel 7.4 is here. Unlike most of the minor releases of the JavaScript compiler, not only have new ECMAScript proposals been implemented. This time also upgrades are included. Among them is the support for TypeScript 3.4, which is currently only available as a release candidate. In addition, core-js has been updated to version 3.

core-js @ 3: What’s new in Babel 7.4?

core-js is a polyfill for the standard JavaScript library, which includes support for the official ECMAScript features as well as numerous proposals. In addition, core-js supports some of the WHATWG and W3C standards if they are relevant to cross-platform development or ECMAScript itself. core-js @ 3 was also released just a few days ago. In the new version, some ECMAScript features that were included in the standard in 2018/19 have been marked as stable. In addition, core-js @ 3 supports many new methods that are currently in the staging process of ECMAScript. These include, for example, the set methods that are currently on Stage 2 and the collection methods from Stage 1. In the release notes for core-js @ 3, the developers of the tool provide an overview of these and all other newly added proposals and applications changes.

For Babel 7.4, the implementation of core-js @ 3 changes the way to identify the polyfills needed for an environment. So far, @babel/preset-env exclusively with compat-table , but now this will be supplemented by the test suite from core-js @ 3. The Babel team expects this to increase the accuracy of polyfill selection.

ECMAScript innovations in Babel

In addition, the new Babel release supports the ECMAScript proposal for a syntax for partially applying argument lists to a call expression. The proposal that that ? as a placeholder for arguments, is currently on Stage 1 in the ECMAScript process. Also for the support of Class Private Features there was another update in Babel. Now also static private methods are supported. Regarding the compatibility of Babel to ECMAScript Nicolò Ribaudo reported in the blog post to the latest Babel release that this version passed 98.97 percent of the ECMAScript test suite.

Also new is a parser option that makes parentheses useful in JavaScript code: createParenthesizedExpressions . More information about these and other improvements to Babel 7.4 can be found in the official blog for the compiler .

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