New JS API Release Candidate is Live

Posted 21 November 2021 by Natalie Weizenbaum

The new JavaScript API that we announced a few months ago is now fully implemented in Dart Sass and ready for you to try! The new API is designed to be more idiomatic, performant, and usable than the old one, and we hope it’ll be adopted swiftly by tooling packages.

Because this is such a substantial addition, we want to give users a chance to kick the tires a bit before we set it in stone, so we’ve released it as a release candidate in Dart Sass 1.45.0-rc.1. Download it, try it out, and let us know what you think by filing issues or sending us a tweet. Unless major changes are necessary, we plan to make a stable release some time next week.

How to use it permalinkHow to use it

The new API comes with four new entrypoint functions: compile() and compileAsync() take Sass file paths and return the result of compiling them to CSS, while compileString() and compileStringAsync() take a string of Sass source and compile it to CSS. Unlike the old API, the async functions all return Promises. As with the old API, the synchronous functions are substantially faster than their async counterparts, so we recommend using them if at all possible.

const sass = require('sass');

const result = sass.compileString(`
h1 {
  font-size: 40px;
  code {
    font-face: Roboto Mono;

Check out the API docs for more details on the API, including the brand-new importer and custom function APIs.

What about the old API? permalinkWhat about the old API?

Once the new API has a stable release, we’ll officially consider the old API to be deprecated. Since it’s still widely-used, we’ll continue to maintain it for a good long while going forward. Expect it to start printing a deprecation warning in a year or so, and to be disabled for good once we release Dart Sass 2.0.0.