如何打一个既支持cjs，又支持esm的npm包（）如何打一个既支持cjs，又支持

模块化是一个老生常谈的问题了，打包工具层出不穷。
那么，如何利用这些打包工具去打出既支持cjs，又支持esm的npm包呢。
这篇文章不涉及概念，是一些打包实测。
demo repo: https://github.com/FrankKai/n...
可以clone下来，本地构建测试。

tsc
rollup
webpack
esbuild

tsc

tsconfig.json
tsconfig-esm.json
package.json

cjs 【如何打一个既支持cjs，又支持esm的npm包（）】tsconfig.json

{ "compilerOptions": { "target": "ES2015", "module": "commonjs", "outDir": "./dist/cjs", "esModuleInterop": true, "moduleResolution": "node" } }

esm tsconfig-esm.json

{ "extends": "./tsconfig.json","compilerOptions": { "target": "es2015", "module": "es2015", "outDir": "./dist/esm", "moduleResolution": "node" } }

package.json

{ "main": "./dist/cjs/index.js", "module": "./dist/esm/index.js", "scripts": { "build": "rm -rf dist && tsc -p tsconfig.json && tsc -p tsconfig-esm.json" }, }

rollup

rollup.config.js
package.json

rollup.config.js

export default [ { input: "src/index.js", output: [ { file: "dist/index.cjs.js", format: "cjs" }, { file: "dist/index.esm.js", format: "es" }, ], }, ];

package.json

{ "main": "dist/index.cjs.js", "module": "dist/index.esm.js", "scripts": { "build": "rollup -c", }, }

webpack

webpack.config.js
package.json

webpack.config.js

const path = require("path"); module.exports = { mode: 'none', entry: { "index.cjs": { import: './src/index.js', library: { type: 'commonjs2', },}, "index.esm": { import: './src/index.js', library: { type: 'module', }, }, }, output: { path: path.resolve(__dirname, 'dist'), filename: "[name].js", clean: true, }, experiments: { outputModule: true } };

package.json

{ "main": "dist/index.cjs.js", "module": "dist/index.esm.js", "scripts": { "build": "webpack", }, "devDependencies": { "webpack": "^5.38.1", "webpack-cli": "^4.7.2" } }

esbuild

package.json

{ "main": "dist/index.cjs.js", "module": "dist/index.esm.js", "scripts": { "esbuild:cjs": "esbuild ./src/index.js --bundle --outfile=dist/index.cjs.js --format=cjs", "esbuild:esm": "esbuild ./src/index.js --bundle --outfile=dist/index.esm.js --format=esm", "build": "npm run esbuild:cjs && npm run esbuild:esm" }, "devDependencies": { "esbuild": "^0.14.49" }, }