“infamous triplet” set up to support TS, faux esm, esm and commonjs

import-flavors.js

// https://github.com/fastify/fastify/blob/224dc104260ad26f9baa0e46962f917963d41fe5/fastify.js#L711
// https://twitter.com/matteocollina/status/1493198259212406784
/**
 * These export configurations enable JS and TS developers
 * to consumer fastify in whatever way best suits their needs.
 * Some examples of supported import syntax includes:
 * - `const fastify = require('fastify')`
 * - `const { fastify } = require('fastify')`
 * - `import * as Fastify from 'fastify'`
 * - `import { fastify, TSC_definition } from 'fastify'`
 * - `import fastify from 'fastify'`
 * - `import fastify, { TSC_definition } from 'fastify'`
 */
module.exports = fastify
module.exports.fastify = fastify
module.exports.default = fastify

package.json

{
  "name": "fastify",
  "version": "3.27.1",
  "description": "Fast and low overhead web framework, for Node.js",
  "main": "fastify.js",
  "type": "commonjs",
  "types": "fastify.d.ts",
  ... 
}