fix: answer DOM probes on NativeScriptDocument instead of throwing

edusperoni · edusperoni · commit 440cce933298 · 2026-07-25T15:17:01.000-03:00
* Angular discovers some optional configuration by reading the DOM. The
  CSP_NONCE default factory, for example, evaluates
  `DOCUMENT.body.querySelector('[ngCspNonce]')`. `NativeScriptDocument.body`
  was a hollow object, so the optional chaining in those probes did not help
  and they failed with `body?.querySelector is not a function`. Signal forms
  reach this on the first `[formField]` binding, which crashed every
  signal-form dialog at construction.
* `querySelector`, `querySelectorAll`, `getElementById`,
  `getElementsByTagName` and `getElementsByClassName` now answer "nothing
  found" on the document and on `body`/`head`. `createElement` still throws,
  since constructing real nodes is a caller bug rather than a probe.
* CSP_NONCE is also provided as `null`, as there is no CSP in a NativeScript
  runtime. It has to be a root provider: the root injector resolves
  `providedIn: 'root'` tokens itself before consulting the platform injector,
  so providing it in COMMON_PROVIDERS would have had no effect.
diff --git a/packages/angular/src/lib/nativescript.ts b/packages/angular/src/lib/nativescript.ts
@@ -1,5 +1,5 @@
 import { ViewportScroller, XhrFactory, ɵNullViewportScroller as NullViewportScroller } from '@angular/common';
-import { ApplicationModule, ErrorHandler, Inject, NgModule, NO_ERRORS_SCHEMA, Optional, Provider, RendererFactory2, SkipSelf, StaticProvider, ɵINJECTOR_SCOPE as INJECTOR_SCOPE } from '@angular/core';
+import { ApplicationModule, CSP_NONCE, ErrorHandler, Inject, NgModule, NO_ERRORS_SCHEMA, Optional, Provider, RendererFactory2, SkipSelf, StaticProvider, ɵINJECTOR_SCOPE as INJECTOR_SCOPE } from '@angular/core';
 import { Color, Device, View } from '@nativescript/core';
 import { AppHostView } from './app-host-view';
 import { NativescriptXhrFactory } from './nativescript-xhr-factory';
@@ -39,6 +39,10 @@ export const NATIVESCRIPT_MODULE_STATIC_PROVIDERS: StaticProvider[] = [
   { provide: NAMESPACE_FILTERS, useClass: PlatformNamespaceFilter, deps: [DEVICE], multi: true },
   { provide: DEVICE, useValue: Device },
   { provide: XhrFactory, useClass: NativescriptXhrFactory, deps: [] },
+  // No CSP in a NativeScript runtime. Providing it also stops the token's default
+  // factory reading `DOCUMENT.body.querySelector()`. Must stay root-scoped: the root
+  // injector resolves `providedIn: 'root'` tokens before consulting the platform.
+  { provide: CSP_NONCE, useValue: null },
 ];
 export const NATIVESCRIPT_MODULE_PROVIDERS: Provider[] = [{ provide: ViewportScroller, useClass: NullViewportScroller }];
 
diff --git a/packages/angular/src/lib/platform-nativescript.ts b/packages/angular/src/lib/platform-nativescript.ts
@@ -37,12 +37,41 @@ export class NativeScriptSanitizer extends Sanitizer {
 //   };
 // }
 
+/**
+ * Angular probes the DOM to discover optional configuration it may have been handed
+ * out of band - a `ngCspNonce` attribute on `<body>`, a transfer state `<script>` in
+ * the document. None of that can exist here, so the lookups answer "nothing found".
+ * Leaving the methods undefined instead surfaces as a `TypeError` thrown from deep
+ * inside framework code, since `document.body` is present and merely hollow.
+ */
+const NO_DOM_QUERIES = {
+  querySelector: () => null,
+  querySelectorAll: () => [],
+  getElementById: () => null,
+  getElementsByTagName: () => [],
+  getElementsByClassName: () => [],
+  getAttribute: () => null,
+  hasAttribute: () => false,
+};
+
 export class NativeScriptDocument {
   // Required by the AnimationDriver
   public body: any = {
     isOverride: true,
+    ...NO_DOM_QUERIES,
   };
 
+  public head: any = {
+    ...NO_DOM_QUERIES,
+  };
+
+  public querySelector = NO_DOM_QUERIES.querySelector;
+  public querySelectorAll = NO_DOM_QUERIES.querySelectorAll;
+  public getElementById = NO_DOM_QUERIES.getElementById;
+  public getElementsByTagName = NO_DOM_QUERIES.getElementsByTagName;
+  public getElementsByClassName = NO_DOM_QUERIES.getElementsByClassName;
+
+  // Deliberately still throws: constructing real nodes is a caller bug, not a probe.
   createElement(tag: string) {
     throw new Error('NativeScriptDocument is not DOM Document. There is no createElement() method.');
   }
