This project collects statistics about ES Module adoption across TypeScript and JavaScript projects, across NPM and Github.

Context

ES Modules (import/export) were introduced in 2015, and NodeJS has supported type=module/commonjs, .mjs, and .cjs, with the goal of replacing .js, since 2019.

This repo tries to understand the degree to which .mjs, .cjs, and type have been adopted across the JavaScript/TypeScript ecosystems.

Also see this history.

Results

tl;dr:

1. Adoption of ES Modules is between 8-27%, depending how you measure it
2. Adoption of ES Modules is between 9-27% via package.json, and 0-6% via file extension

Github

1.8k most popular JS/TS repos, via Github API

Metric	JavaScript	TypeScript
% of package.jsons that have a type field	9%	13%
% of package.jsons that have type=module	8%	12%
% of files that use ESM file extensions (.mjs, .cjs, .mts, etc.)	6%	<1%

NPM

935 packages with the most weekly downloads, via NPM API

Metric	%
% of package.jsons that have a type field (or exports field with commonjs or module defined)	27%
% of package.jsons that have type=module	16%
% of files that use ESM file extensions (.mjs, .cjs, .mts, etc.)	<1%
% of files that are ES modules (either via package.json or via file extension)	22%

Pull NPM data

$ curl -L -O https://replicate.npmjs.com/_all_docs
$ node --loader ts-node/esm src/getNPMDownloadStats.ts
$ node --loader ts-node/esm src/getTopNPMRepos.ts
$ node --loader ts-node/esm src/getNPMModuleTypes.ts
$ node --loader ts-node/esm src/getNPMTotals.ts

Generate data

$ npm install
$ node --loader ts-node/esm src/getRepos.ts
$ node --loader ts-node/esm src/getFiletypes.ts
$ node --loader ts-node/esm src/getModuleTypes.ts
$ node --loader ts-node/esm src/getTotals.ts