es-modules.md

Using ES modules in AVA

Translations: Français

As of Node.js 12.17, ECMAScript Modules are natively supported in Node.js itself. AVA 3.3 supports ESM test files, however support is incomplete. The ESM support project tracks our progress.

If you use TypeScript with ts-node please see our Typescript recipe for setup instructions.

Using the esm package

If you're using Node.js 10 and AVA 3 and you want to use the ESM syntax, without relying on Node.js' implementation, your best bet is to use the esm package. Make sure to use the .js extension and do not set "type": "module" in package.json.

Note: The esm package is no longer supported in AVA 4.

Here's how you get it working with AVA.

First, install esm:

$ npm install esm

Configure it in your package.json or ava.config.* file, and add it to AVA's "require" option as well. Make sure to add it as the first item.

package.json:

{
	"ava": {
		"require": [
			"esm"
		]
	}
}

You can now use native ES modules with AVA:

// sum.js
export default function sum(a, b) {
	return a + b;
};

// test.js
import test from 'ava';
import sum from './sum';

test('2 + 2 = 4', t => {
	t.is(sum(2, 2), 4);
});