René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"url:  URLPatternInit dictionary conversion does not follow WebIDL semantics","articleBody":"### Version\n\nlatest main branch\n\n### Platform\n\n```text\n7.1.4-arch1-1\n```\n\n### Subsystem\n\nurl\n\n### What steps will reproduce the bug?\n\n```js\n  const { URLPattern } = require('node:url');\n\n  // Member access order\n  const accessed = [];\n\n  new URLPattern(new Proxy({}, {\n    get(target, property, receiver) {\n      accessed.push(property);\n      return Reflect.get(target, property, receiver);\n    },\n  }));\n\n  console.log(accessed);\n\n  // Absent members in URLPatternResult.inputs\n  const pattern = new URLPattern({ pathname: '/x' });\n  const input = pattern.exec({ pathname: '/x' }).inputs[0];\n\n  console.log(Object.keys(input));\n  console.log('protocol' in input);\n  console.log({ ...input });\n```\n\n### How often does it reproduce? Is there a required condition?\n\nEvery\n\n### What is the expected behavior? Why is that the expected behavior?\n\n  WebIDL dictionary members should be accessed in lexicographical order:\n\n```js\n  [\n    'baseURL',\n    'hash',\n    'hostname',\n    'password',\n    'pathname',\n    'port',\n    'protocol',\n    'search',\n    'username',\n  ]\n\n```\n  The echoed dictionary should contain only members present after WebIDL conversion:\n\n```js\n  Object.keys(input);\n  // ['pathname']\n\n  'protocol' in input;\n  // false\n\n  { ...input };\n  // { pathname: '/x' }\n```\n\n  An optional member explicitly set to undefined should also be treated as absent.\n\n  The member access-order difference affects the URLPattern constructor, exec(), and test(). The result-shape\n  difference is observable through URLPatternResult.inputs.\n\n### What do you see instead?\n\n  The members are accessed in the following order:\n\n```js\n  [\n    'protocol',\n    'username',\n    'password',\n    'hostname',\n    'port',\n    'pathname',\n    'search',\n    'hash',\n    'baseURL',\n  ]\n```\n\n  The echoed input exposes all dictionary members:\n\n```js\n  Object.keys(input);\n  // [\n  //   'protocol',\n  //   'username',\n  //   'password',\n  //   'hostname',\n  //   'search',\n  //   'hash',\n  //   'baseURL',\n  // ]\n\n  'protocol' in input;\n  // true\n```\n\n  Absent members are enumerable own properties whose values are undefined.\n\n### Additional information\n\nRefs: https://urlpattern.spec.whatwg.org/#url-pattern-match\nRefs: https://webidl.spec.whatwg.org/#es-dictionary)\nRefs: https://webidl.spec.whatwg.org/#idl-dictionaries\nRefs: https://webidl.spec.whatwg.org/#es-dictionary)","author":{"url":"https://github.com/Archkon","@type":"Person","name":"Archkon"},"datePublished":"2026-07-27T14:13:47Z","url":"https://github.com/nodejs/node/issues/64780"}