esm-specifiers.md

ECMAScript module specifiers

There are three kinds of module specifiers:

• Absolute specifiers are full URLs that are used directly – for example:

  'file:///opt/nodejs/config.mjs'
  'https://unpkg.com/liltest@0.0.5/dist/liltest.js'
  

• Relative specifiers are relative URLs that are resolved against the URL of the importing module – for example:

  // URL of importing module
  const u = 'https://example.com/public/dir/a.js';
  assert.equal(
    new URL('./b.js', u).toString(),
    'https://example.com/public/dir/b.js'
  );
  assert.equal(
    new URL('../c.mjs', u).toString(),
    'https://example.com/public/c.mjs'
  );
  assert.equal(
    new URL('../../tmp/d.js', u).toString(),
    'https://example.com/tmp/d.js'
  );

• Bare specifiers are paths (without protocol and domain) that start with neither slashes nor dots – for example:

  'some-package'
  'lodash/fp/add'
  

Source: https://nodejs.org/api/esm.html#terminology