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Esprima 2.0 Released

February 6th, 2015

Last week, the jQuery Foundation announced our adoption of the Esprima project, the widely used JavaScript parser that powers many code analysis tools. Today we’re pleased to announce the release of version 2.0, now available on npm.

Up until now, the official releases of Esprima have only parsed ECMAScript 5 standard syntax. However, the experimental “harmony” branch has been adding ECMAScript 2015 (also popularly known as ES6) features for quite some time. A lot of the work there has been driven by Facebook. Now that the syntax for many ES6 features has stabilized and even shipped on some browsers, there is a need for tools that support the new syntax.

Esprima 2.0 introduces many stable ES6 features brought from the harmony branch, where they’ve been pretty reliable. This new baseline for Esprima makes it possible for tools such as code coverage analysis, style checkers, and linters to start to process the new ES6 syntax.

Since ES5 is likely to be with us for quite a while longer, Esprima 1.x will continue to be maintained for now in order to provide ES5-only parsing. Tools that currently use Esprima 1.x can continue to do so until they are ready and able to process ES6 constructs.

The 2.1 release of Esprima should follow relatively quickly, based on feedback on the stability of the 2.0 release. That means the Esprima team needs feedback from the makers of Esprima-based tools to know whether there are any problems. If you have built an Esprima-based tool and have problems with this release, please report them. (Note that the project is now using GitHub for issues rather than Google Code.)

We’re excited to see where Esprima goes next!