url: extend URLSearchParams constructor

PR-URL: #12507
Fixes: #10635
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: TimothyGu

lib/internal/url.js

@@ -614,11 +614,53 @@ function defineIDLClass(proto, classStr, obj) {
 }
 
 class URLSearchParams {
-  constructor(init = '') {
-    if (init instanceof URLSearchParams) {
-      const childParams = init[searchParams];
-      this[searchParams] = childParams.slice();
+  // 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] = [];
+    } else if (typeof init === 'object') {
+      const method = init[Symbol.iterator];
+      if (method === this[Symbol.iterator]) {
+        // 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) {
+        if (typeof method !== 'function') {
+          throw new TypeError('Query pairs must be iterable');
+        }
+
+        // sequence<sequence<USVString>>
+        // Note: per spec we have to first exhaust the lists then process them
+        const pairs = [];
+        for (const pair of init) {
+          if (typeof pair !== 'object' ||
+              typeof pair[Symbol.iterator] !== 'function') {
+            throw new TypeError('Each query pair must be iterable');
+          }
+          pairs.push(Array.from(pair));
+        }
+
+        this[searchParams] = [];
+        for (const pair of pairs) {
+          if (pair.length !== 2) {
+            throw new TypeError('Each query pair must be a name/value tuple');
+          }
+          this[searchParams].push(String(pair[0]), String(pair[1]));
+        }
+      } else {
+        // record<USVString, USVString>
+        this[searchParams] = [];
+        for (const key of Object.keys(init)) {
+          const value = String(init[key]);
+          this[searchParams].push(key, value);
+        }
+      }
     } else {
+      // USVString
       init = String(init);
       if (init[0] === '?') init = init.slice(1);
       initSearchParams(this, init);

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

@@ -4,7 +4,8 @@ const common = require('../common');
 const assert = require('assert');
 const URLSearchParams = require('url').URLSearchParams;
 const {
-  test, assert_equals, assert_true, assert_false
+  test, assert_equals, assert_true,
+  assert_false, assert_throws, assert_array_equals
 } = common.WPT;
 
 /* eslint-disable */
@@ -40,10 +41,10 @@ test(() => {
     assert_equals(params.__proto__, URLSearchParams.prototype, 'expected URLSearchParams.prototype as prototype.');
 }, "URLSearchParams constructor, empty string as argument")
 
-// test(() => {
-//     params = new URLSearchParams({});
-//     assert_equals(params + '', "");
-// }, 'URLSearchParams constructor, {} as argument');
+test(() => {
+    params = new URLSearchParams({});
+    assert_equals(params + '', "");
+}, 'URLSearchParams constructor, {} as argument');
 
 test(function() {
     var params = new URLSearchParams('a=b');
@@ -142,39 +143,39 @@ test(function() {
     assert_equals(params.get('a\uD83D\uDCA9b'), 'c');
 }, 'Parse %f0%9f%92%a9');  // Unicode Character 'PILE OF POO' (U+1F4A9)
 
-// test(function() {
-//     var params = new URLSearchParams([]);
-//     assert_true(params != null, 'constructor returned non-null value.');
-//     params = new URLSearchParams([['a', 'b'], ['c', 'd']]);
-//     assert_equals(params.get("a"), "b");
-//     assert_equals(params.get("c"), "d");
-//     assert_throws(new TypeError(), function() { new URLSearchParams([[1]]); });
-//     assert_throws(new TypeError(), function() { new URLSearchParams([[1,2,3]]); });
-// }, "Constructor with sequence of sequences of strings");
-
-// [
+test(function() {
+    var params = new URLSearchParams([]);
+    assert_true(params != null, 'constructor returned non-null value.');
+    params = new URLSearchParams([['a', 'b'], ['c', 'd']]);
+    assert_equals(params.get("a"), "b");
+    assert_equals(params.get("c"), "d");
+    assert_throws(new TypeError(), function() { new URLSearchParams([[1]]); });
+    assert_throws(new TypeError(), function() { new URLSearchParams([[1,2,3]]); });
+}, "Constructor with sequence of sequences of strings");
+
+[
 //   { "input": {"+": "%C2"}, "output": [[" ", "\uFFFD"]], "name": "object with +" },
-//   { "input": {c: "x", a: "?"}, "output": [["c", "x"], ["a", "?"]], "name": "object with two keys" },
-//   { "input": [["c", "x"], ["a", "?"]], "output": [["c", "x"], ["a", "?"]], "name": "array with two keys" }
-// ].forEach((val) => {
-//     test(() => {
-//         let params = new URLSearchParams(val.input),
-//             i = 0
-//         for (let param of params) {
-//             assert_array_equals(param, val.output[i])
-//             i++
-//         }
-//     }, "Construct with " + val.name)
-// })
+  { "input": {c: "x", a: "?"}, "output": [["c", "x"], ["a", "?"]], "name": "object with two keys" },
+  { "input": [["c", "x"], ["a", "?"]], "output": [["c", "x"], ["a", "?"]], "name": "array with two keys" }
+].forEach((val) => {
+    test(() => {
+        let params = new URLSearchParams(val.input),
+            i = 0
+        for (let param of params) {
+            assert_array_equals(param, val.output[i])
+            i++
+        }
+    }, "Construct with " + val.name)
+})
 
-// test(() => {
-//   params = new URLSearchParams()
-//   params[Symbol.iterator] = function *() {
-//     yield ["a", "b"]
-//   }
-//   let params2 = new URLSearchParams(params)
-//   assert_equals(params2.get("a"), "b")
-// }, "Custom [Symbol.iterator]")
+test(() => {
+  params = new URLSearchParams()
+  params[Symbol.iterator] = function *() {
+    yield ["a", "b"]
+  }
+  let params2 = new URLSearchParams(params)
+  assert_equals(params2.get("a"), "b")
+}, "Custom [Symbol.iterator]")
 /* eslint-enable */
 
 // Tests below are not from WPT.
@@ -192,5 +193,17 @@ test(function() {
   params = new URLSearchParams(undefined);
   assert.strictEqual(params.toString(), '');
   params = new URLSearchParams(null);
-  assert.strictEqual(params.toString(), 'null=');
+  assert.strictEqual(params.toString(), '');
+  assert.throws(() => new URLSearchParams([[1]]),
+                /^TypeError: Each query pair must be a name\/value tuple$/);
+  assert.throws(() => new URLSearchParams([[1, 2, 3]]),
+                /^TypeError: Each query pair must be a name\/value tuple$/);
+  assert.throws(() => new URLSearchParams({ [Symbol.iterator]: 42 }),
+                /^TypeError: Query pairs must be iterable$/);
+  assert.throws(() => new URLSearchParams([{}]),
+                /^TypeError: Each query pair must be iterable$/);
+  assert.throws(() => new URLSearchParams(['a']),
+                /^TypeError: Each query pair must be iterable$/);
+  assert.throws(() => new URLSearchParams([{ [Symbol.iterator]: 42 }]),
+                /^TypeError: Each query pair must be iterable$/);
 }