url: don't update URL immediately on update to URLSearchParams

benchmark/url/url-searchparams-append.js

@@ -0,0 +1,19 @@
+'use strict';
+const common = require('../common.js');
+
+const bench = common.createBenchmark(main, {
+  type: ['URL', 'URLSearchParams'],
+  n: [1e3, 1e6],
+});
+
+function main({ type, n }) {
+  const params = type === 'URL' ?
+    new URL('https://nodejs.org').searchParams :
+    new URLSearchParams();
+
+  bench.start();
+  for (let i = 0; i < n; i++) {
+    params.append('test', i);
+  }
+  bench.end(n);
+}

benchmark/url/url-searchparams-update.js

@@ -0,0 +1,23 @@
+'use strict';
+const common = require('../common.js');
+
+const bench = common.createBenchmark(main, {
+  searchParams: ['true', 'false'],
+  property: ['pathname', 'search'],
+  n: [1e6],
+});
+
+function main({ searchParams, property, n }) {
+  const url = new URL('https://nodejs.org');
+  if (searchParams === 'true') url.searchParams; // eslint-disable-line no-unused-expressions
+
+  const method = property === 'pathname' ?
+    (x) => url.pathname = `/${x}` :
+    (x) => url.search = `?${x}`;
+
+  bench.start();
+  for (let i = 0; i < n; i++) {
+    method(i);
+  }
+  bench.end(n);
+}

lib/internal/url.js

@@ -206,6 +206,7 @@ class URLContext {
   }
 }
 
+let setURLSearchParamsModified;
 let setURLSearchParamsContext;
 let getURLSearchParamsList;
 let setURLSearchParams;
@@ -475,8 +476,9 @@ class URLSearchParams {
     name = StringPrototypeToWellFormed(`${name}`);
     value = StringPrototypeToWellFormed(`${value}`);
     ArrayPrototypePush(this.#searchParams, name, value);
+
     if (this.#context) {
-      this.#context.search = this.toString();
+      setURLSearchParamsModified(this.#context);
     }
   }
 
@@ -509,8 +511,9 @@ class URLSearchParams {
         }
       }
     }
+
     if (this.#context) {
-      this.#context.search = this.toString();
+      setURLSearchParamsModified(this.#context);
     }
   }
 
@@ -615,7 +618,7 @@ class URLSearchParams {
     }
 
     if (this.#context) {
-      this.#context.search = this.toString();
+      setURLSearchParamsModified(this.#context);
     }
   }
 
@@ -664,7 +667,7 @@ class URLSearchParams {
     }
 
     if (this.#context) {
-      this.#context.search = this.toString();
+      setURLSearchParamsModified(this.#context);
     }
   }
 
@@ -769,6 +772,20 @@ function isURL(self) {
 class URL {
   #context = new URLContext();
   #searchParams;
+  #searchParamsModified;
+
+  static {
+    setURLSearchParamsModified = (obj) => {
+      // When URLSearchParams changes, we lazily update URL on the next read/write for performance.
+      obj.#searchParamsModified = true;
+
+      // If URL has an existing search, remove it without cascading back to URLSearchParams.
+      // Do this to avoid any internal confusion about whether URLSearchParams or URL is up-to-date.
+      if (obj.#context.hasSearch) {
+        obj.#updateContext(bindingUrl.update(obj.#context.href, updateActions.kSearch, ''), false);
+      }
+    };
+  }
 
   constructor(input, base = undefined) {
     markTransferMode(this, false, false);
@@ -814,7 +831,33 @@ class URL {
     return `${constructor.name} ${inspect(obj, opts)}`;
   }
 
-  #updateContext(href) {
+  #getSearchFromContext() {
+    if (!this.#context.hasSearch) return '';
+    let endsAt = this.#context.href.length;
+    if (this.#context.hasHash) endsAt = this.#context.hash_start;
+    if (endsAt - this.#context.search_start <= 1) return '';
+    return StringPrototypeSlice(this.#context.href, this.#context.search_start, endsAt);
+  }
+
+  #getSearchFromParams() {
+    if (!this.#searchParams?.size) return '';
+    return `?${this.#searchParams}`;
+  }
+
+  #checkSearchParams() {
+    // If URLSearchParams has been modified, reflect that back into URL, and do not cascade back.
+    // This is done lazily to greatly improve performance when URLSearchParams is updated repeatedly.
+    if (this.#searchParamsModified) {
+      const href = bindingUrl.update(this.#context.href, updateActions.kSearch, this.#getSearchFromParams());
+      this.#updateContext(href, false);
+      this.#searchParamsModified = false;
+    }
+  }
+
+  #updateContext(href, updateSearchParams = !!this.#searchParams) {
+    const previousSearch = updateSearchParams && (this.#searchParamsModified ?
+      this.#getSearchFromParams() : this.#getSearchFromContext());
+
     this.#context.href = href;
 
     const {
@@ -839,20 +882,26 @@ class URL {
     this.#context.hash_start = hash_start;
     this.#context.scheme_type = scheme_type;
 
-    if (this.#searchParams) {
-      if (this.#context.hasSearch) {
-        setURLSearchParams(this.#searchParams, this.search);
+    // If URLSearchParams exists, and the search has changed, update it.
+    // Otherwise, check if URLSearchParams has been modified.
+    if (updateSearchParams) {
+      const currentSearch = this.#getSearchFromContext();
+      if (previousSearch !== currentSearch) {
+        setURLSearchParams(this.#searchParams, currentSearch);
+        this.#searchParamsModified = false;
       } else {
-        setURLSearchParams(this.#searchParams, undefined);
+        this.#checkSearchParams();
       }
     }
   }
 
   toString() {
+    this.#checkSearchParams();
     return this.#context.href;
   }
 
   get href() {
+    this.#checkSearchParams();
     return this.#context.href;
   }
 
@@ -1002,11 +1051,8 @@ class URL {
   }
 
   get search() {
-    if (!this.#context.hasSearch) { return ''; }
-    let endsAt = this.#context.href.length;
-    if (this.#context.hasHash) { endsAt = this.#context.hash_start; }
-    if (endsAt - this.#context.search_start <= 1) { return ''; }
-    return StringPrototypeSlice(this.#context.href, this.#context.search_start, endsAt);
+    this.#checkSearchParams();
+    return this.#getSearchFromContext();
   }
 
   set search(value) {
@@ -1020,8 +1066,9 @@ class URL {
   get searchParams() {
     // Create URLSearchParams on demand to greatly improve the URL performance.
     if (this.#searchParams == null) {
-      this.#searchParams = new URLSearchParams(this.search);
+      this.#searchParams = new URLSearchParams(this.#getSearchFromContext());
       setURLSearchParamsContext(this.#searchParams, this);
+      this.#searchParamsModified = false;
     }
     return this.#searchParams;
   }
@@ -1041,6 +1088,7 @@ class URL {
   }
 
   toJSON() {
+    this.#checkSearchParams();
     return this.#context.href;
   }