url: improve URLSearchParams creation performance

lib/internal/url.js

@@ -2,6 +2,7 @@
 
 const {
  Array,
+ ArrayIsArray,
  ArrayPrototypeJoin,
  ArrayPrototypeMap,
  ArrayPrototypePush,
@@ -151,52 +152,74 @@ function isURLSearchParams(self) {
 }
 
 class URLSearchParams {
+ [searchParams] = [];
+
+ // "associated url object"
+ [context] = null;
+
  // 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) {
- if (init === null || init === undefined) {
-this[searchParams] = [];
+ if (init == null) {
+// Do nothing
  } else if (typeof init === 'object' || typeof init === 'function') {
  const method = init[SymbolIterator];
  if (method === this[SymbolIterator]) {
  // 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 && method !== undefined) {
+ } else if (method != null) {
+ // Sequence<sequence<USVString>>
  if (typeof method !== 'function') {
  throw new ERR_ARG_NOT_ITERABLE('Query pairs');
  }
 
- // Sequence<sequence<USVString>>
- // Note: per spec we have to first exhaust the lists then process them
- const pairs = [];
+ // The following implementationd 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 ((typeof pair !== 'object' && typeof pair !== 'function') ||
- pair === null ||
- typeof pair[SymbolIterator] !== 'function') {
+ if (pair == null) {
  throw new ERR_INVALID_TUPLE('Each query pair', '[name, value]');
- }
- const convertedPair = [];
- for (const element of pair)
- ArrayPrototypePush(convertedPair, toUSVString(element));
- ArrayPrototypePush(pairs, convertedPair);
- }
+ } else if (ArrayIsArray(pair)) {
+ // If innerSequence's size is not 2, then throw a TypeError.
+ if (pair.length !== 2) {
+ throw new ERR_INVALID_TUPLE('Each query pair', '[name, value]');
+ }
+ // Append (innerSequence[0], innerSequence[1]) to querys list.
+ ArrayPrototypePush(this[searchParams], toUSVString(pair[0]), toUSVString(pair[1]));
+ } else {
+ if (((typeof pair !== 'object' && typeof pair !== 'function') ||
+ typeof pair[SymbolIterator] !== 'function')) {
+ throw new ERR_INVALID_TUPLE('Each query pair', '[name, value]');
+ }
 
- this[searchParams] = [];
- for (const pair of pairs) {
- if (pair.length !== 2) {
- throw new ERR_INVALID_TUPLE('Each query pair', '[name, value]');
+ let length = 0;
+
+ for (const element of pair) {
+ length++;
+ ArrayPrototypePush(this[searchParams], toUSVString(element));
+ }
+
+ // If innerSequence's size is not 2, then throw a TypeError.
+ if (length !== 2) {
+ throw new ERR_INVALID_TUPLE('Each query pair', '[name, value]');
+ }
  }
- ArrayPrototypePush(this[searchParams], pair[0], pair[1]);
  }
  } else {
  // Record<USVString, USVString>
  // Need to use reflection APIs for full spec compliance.
  const visited = {};
- this[searchParams] = [];
  const keys = ReflectOwnKeys(init);
  for (let i = 0; i < keys.length; i++) {
  const key = keys[i];
@@ -218,13 +241,10 @@ class URLSearchParams {
  }
  }
  } else {
- // USVString
+ // https://url.spec.whatwg.org/#dom-urlsearchparams-urlsearchparams
  init = toUSVString(init);
  this[searchParams] = init ? parseParams(init) : [];
  }
-
- // "associated url object"
- this[context] = null;
  }
 
  [inspect.custom](recurseTimes, ctx) {

test/parallel/test-whatwg-url-custom-searchparams-constructor.js

@@ -47,6 +47,10 @@ function makeIterableFunc(array) {
  assert.throws(() => new URLSearchParams([null]), tupleError);
  assert.throws(() => new URLSearchParams([{ [Symbol.iterator]: 42 }]),
  tupleError);
+
+ assert.throws(() => new URLSearchParams(
+ makeIterableFunc([['key', 'val', 'val2']])
+ ), tupleError);
 }
 
 {