build(docs-infra): add NgModules references to provided injectables (#41960)

Parse the `providers` property of each NgModule doc and add this doc to
the `ngModules` property of each provided injectable.

PR Close #41960

aio/tools/transforms/angular-api-package/processors/processNgModuleDocs.js

@@ -158,6 +158,19 @@ module.exports = function processNgModuleDocs(getDocFromAlias, createDocMessage,
     processNgModuleProviders(ngModuleDoc) {
       // Add providers from the NgModule decorator.
       const providers = ngModuleDoc.ngmoduleOptions.providers || [];
+
+      // Update injectables which are provided by this NgModule
+      for (const provider of providers) {
+        const injectable = parseProvider(provider);
+        const injectableDocs = getDocFromAlias(injectable, ngModuleDoc);
+        if (injectableDocs.length !== 1) {
+          continue;
+        }
+        const injectableDoc = injectableDocs[0];
+        injectableDoc.ngModules = injectableDoc.ngModules || [];
+        injectableDoc.ngModules.push(ngModuleDoc);
+      }
+
       // And also add those associated via the `Injectable` `providedIn` property.
       if (Array.isArray(ngModuleDoc.providers)) {
         for (const provider of ngModuleDoc.providers) {
@@ -168,6 +181,7 @@ module.exports = function processNgModuleDocs(getDocFromAlias, createDocMessage,
       if (providers.length > 0) {
         ngModuleDoc.providers = providers;
       }
+
     }
   };
 
@@ -191,6 +205,15 @@ module.exports = function processNgModuleDocs(getDocFromAlias, createDocMessage,
   }
 };
 
+function parseProvider(provider) {
+  const match = /\{\s*provide:\s*(\w+)\s*,/.exec(provider);
+  if (match) {
+    return match[1];
+  } else {
+    return provider;
+  }
+}
+
 /**
  * Compute the name of the array that will hold items of this type in the NgModule document.
  */

aio/tools/transforms/angular-api-package/processors/processNgModuleDocs.spec.js

@@ -150,6 +150,24 @@ describe('processNgModuleDocs processor', () => {
     expect(nonInjectable.ngModules).toBeUndefined();
   });
 
+  it('should link injectables that are parsed out of `@NgModule` decorators', () => {
+    const ngModule1 = { docType: 'ngmodule', id: 'NgModule1', ngmoduleOptions: { providers: ['Injectable1', '{ provide: Injectable2, useClass: Injectable2 }'] } };
+    const ngModule2 = { docType: 'ngmodule', id: 'NgModule2', ngmoduleOptions: { providers: ['{ provide: Injectable3, useValue: {} }'] } };
+    const injectable1 = { docType: 'class', name: 'Injectable1', aliases: ['Injectable1'] };
+    const injectable2 = { docType: 'class', name: 'Injectable2', aliases: ['Injectable2'] };
+    const injectable3 = { docType: 'class', name: 'Injectable3', aliases: ['Injectable3'] };
+
+    const aliasMap = injector.get('aliasMap');
+    aliasMap.addDoc(injectable1);
+    aliasMap.addDoc(injectable2);
+    aliasMap.addDoc(injectable3);
+    processor.$process([ngModule1, ngModule2, injectable1, injectable2, injectable3]);
+
+    expect(injectable1.ngModules).toEqual([ngModule1]);
+    expect(injectable2.ngModules).toEqual([ngModule1]);
+    expect(injectable3.ngModules).toEqual([ngModule2]);
+  });
+
   it('should error if an injectable that has a `providedIn` property that references an unknown NgModule doc', () => {
     const log = injector.get('log');
     const injectable = { docType: 'class', name: 'Injectable1', decorators: [{ name: 'Injectable', argumentInfo: [{ providedIn: 'NgModuleRef' }] }] };