Class URLSearchParams

lib/internal/url.js:313–750

class URLSearchParams {
  #searchParams = [];

  // "associated url object"
  #context;

  static {
    setURLSearchParamsContext = (obj, ctx) => {
      obj.#context = ctx;
    };
    getURLSearchParamsList = (obj) => obj.#searchParams;
    setURLSearchParams = (obj, query) => {
      if (query === undefined) {
        obj.#searchParams = [];
      } else {
        obj.#searchParams = parseParams(query);
      }
    };
  }

  // URL Standard says the default value is '', but as undefined and '' have
  // the same result, undefined is used to prevent unnecessary parsing.
  // Default parameter is necessary to keep URLSearchParams.length === 0 in
  // accordance with Web IDL spec.
  constructor(init = undefined) {
    markTransferMode(this, false, false);

    if (init === undefined) {
      // Do nothing
    } else if (init !== null && (typeof init === 'object' || typeof init === 'function')) {
      const method = init[SymbolIterator];
      if (method === this[SymbolIterator] && #searchParams in init) {
        // While the spec does not have this branch, we can use it as a
        // shortcut to avoid having to go through the costly generic iterator.
        const childParams = init.#searchParams;
        this.#searchParams = childParams.slice();
      } else if (method != null) {
        // Sequence<sequence<USVString>>
        if (typeof method !== 'function') {
          throw new ERR_ARG_NOT_ITERABLE('Query pairs');
        }

        // The following implementation differs from the URL specification:
        // Sequences must first be converted from ECMAScript objects before
        // and operations are done on them, and the operation of converting
        // the sequences would first exhaust the iterators. If the iterator
        // returns something invalid in the middle, whether it would be called
        // after that would be an observable change to the users.
        // Exhausting the iterator and later converting them to USVString comes
        // with a significant cost (~40-80%). In order optimize URLSearchParams
        // creation duration, Node.js merges the iteration and converting
        // iterations into a single iteration.
        for (const pair of init) {
          if (pair == null) {
            throw new ERR_INVALID_TUPLE('Each query pair', '[name, value]');
          } else if (ArrayIsArray(pair)) {
            // If innerSequence's size is not 2, then throw a TypeError.
            if (pair.length !== 2) {