mime 4.1.0: Look up a MIME type from a filename with mime v4

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  "name": "csx-sample-mime-lookup-type",
  "version": "1.0.0",
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    "": {
      "name": "csx-sample-mime-lookup-type",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "mime": "4.1.0"
      }
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    "node_modules/mime": {
      "version": "4.1.0",
      "resolved": "https://registry.npmjs.org/mime/-/mime-4.1.0.tgz",
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      "funding": [
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      "license": "MIT",
      "bin": {
        "mime": "bin/cli.js"
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{
  "name": "csx-sample-mime-lookup-type",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "mime": "4.1.0"
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}

import mime from 'mime';

// mime v4 is ESM-only: require('mime') throws ERR_REQUIRE_ESM, and the v2
// helpers mime.lookup/mime.extension were renamed to getType/getExtension.
// An unknown extension returns null — not '' and not a default type — so
// callers must decide the fallback themselves.
export function typeFor(path) {
  return mime.getType(path);
}

export function extensionFor(type) {
  return mime.getExtension(type);
}

import { strict as assert } from 'node:assert';
import { typeFor, extensionFor } from '../src/index.mjs';

assert.equal(typeFor('reports/data.json'), 'application/json');
assert.equal(typeFor('site.css'), 'text/css');
assert.equal(typeFor('archive.tar.gz'), 'application/gzip');
assert.equal(typeFor('mystery.zzz'), null);

assert.equal(extensionFor('text/plain'), 'txt');
assert.equal(extensionFor('application/json'), 'json');
console.log('CONTRACT PASS: mime v4 getType/getExtension resolved both directions');