diff --git a/packages/compiler-cli/src/ngtsc/typecheck/extended/api/extended_template_checker.ts b/packages/compiler-cli/src/ngtsc/typecheck/extended/api/extended_template_checker.ts
new file mode 100644
index 00000000000..804d628bb22
--- /dev/null
+++ b/packages/compiler-cli/src/ngtsc/typecheck/extended/api/extended_template_checker.ts
@@ -0,0 +1,19 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import * as ts from 'typescript';
+
+/**
+ * Interface to generate extended template diangostics from the component tempaltes.
+ */
+export interface ExtendedTemplateChecker {
+  /**
+   * Run `TemplateCheck`s for a component and return the generated `ts.Diagnostic`s.
+   */
+  getExtendedTemplateDiagnosticsForComponent(component: ts.ClassDeclaration): ts.Diagnostic[];
+}
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/extended/api/index.ts b/packages/compiler-cli/src/ngtsc/typecheck/extended/api/index.ts
new file mode 100644
index 00000000000..fdf52332af7
--- /dev/null
+++ b/packages/compiler-cli/src/ngtsc/typecheck/extended/api/index.ts
@@ -0,0 +1,10 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+export * from './api';
+export * from './extended_template_checker';
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/extended/src/template_checker.ts b/packages/compiler-cli/src/ngtsc/typecheck/extended/src/extended_template_checker.ts
similarity index 58%
rename from packages/compiler-cli/src/ngtsc/typecheck/extended/src/template_checker.ts
rename to packages/compiler-cli/src/ngtsc/typecheck/extended/src/extended_template_checker.ts
index f92e4242164..81eef890c9e 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/extended/src/template_checker.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/extended/src/extended_template_checker.ts
@@ -7,39 +7,42 @@
  */
 
 import * as ts from 'typescript';
+
 import {ErrorCode} from '../../../diagnostics';
 import {TemplateTypeChecker} from '../../api';
-import {TemplateCheck, TemplateContext} from '../api/api';
+import {ExtendedTemplateChecker, TemplateCheck, TemplateContext} from '../api';
 
-/**
- * Run all `TemplateChecks` for a component and return the generated `ts.Diagnostic`s.
- * @param component the `@Component()` class from which the template is obtained
- * @param templateTypeChecker interface to get information about template nodes
- * @param typeChecker program's type checker
- * @param templateChecks specific checks to be run
- * @returns generated `ts.Diagnostic[]`
- */
-export function getExtendedTemplateDiagnosticsForComponent(
-    component: ts.ClassDeclaration, templateTypeChecker: TemplateTypeChecker,
-    typeChecker: ts.TypeChecker, templateChecks: TemplateCheck<ErrorCode>[]): ts.Diagnostic[] {
-  const template = templateTypeChecker.getTemplate(component);
-  // Skip checks if component has no template. This can happen if the user writes a
-  // `@Component()` but doesn't add the template, could happen in the language service
-  // when users are in the middle of typing code.
-  if (template === null) {
-    return [];
+export class ExtendedTemplateCheckerImpl implements ExtendedTemplateChecker {
+  constructor(
+      private readonly templateTypeChecker: TemplateTypeChecker,
+      private readonly typeChecker: ts.TypeChecker,
+      private readonly templateChecks: TemplateCheck<ErrorCode>[]) {}
+
+  getExtendedTemplateDiagnosticsForComponent(component: ts.ClassDeclaration): ts.Diagnostic[] {
+    const template = this.templateTypeChecker.getTemplate(component);
+    // Skip checks if component has no template. This can happen if the user writes a
+    // `@Component()` but doesn't add the template, could happen in the language service
+    // when users are in the middle of typing code.
+    if (template === null) {
+      return [];
+    }
+    const diagnostics: ts.Diagnostic[] = [];
+
+    const ctx = {
+      templateTypeChecker: this.templateTypeChecker,
+      typeChecker: this.typeChecker,
+      component
+    } as TemplateContext;
+
+    for (const check of this.templateChecks) {
+      diagnostics.push(...deduplicateDiagnostics(check.run(ctx, template)));
+    }
+
+    return diagnostics;
   }
-  const diagnostics: ts.Diagnostic[] = [];
-
-  const ctx = {templateTypeChecker, typeChecker, component} as TemplateContext;
-
-  for (const check of templateChecks) {
-    diagnostics.push(...deduplicateDiagnostics(check.run(ctx, template)));
-  }
-
-  return diagnostics;
 }
 
+
 // Filter out duplicated diagnostics, this is possible due to the way the compiler
 // handles desugaring and produces `AST`s. Ex.
 //
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/extended/src/template_checks/invalid_banana_in_box/index.ts b/packages/compiler-cli/src/ngtsc/typecheck/extended/src/template_checks/invalid_banana_in_box/index.ts
index 93ae48b89b4..f782c544d45 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/extended/src/template_checks/invalid_banana_in_box/index.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/extended/src/template_checks/invalid_banana_in_box/index.ts
@@ -9,7 +9,7 @@
 import {TmplAstBoundEvent, TmplAstNode, TmplAstRecursiveVisitor} from '@angular/compiler';
 import * as ts from 'typescript';
 import {ErrorCode} from '../../../../../diagnostics';
-import {TemplateCheck, TemplateContext, TemplateDiagnostic} from '../../../api/api';
+import {TemplateCheck, TemplateContext, TemplateDiagnostic} from '../../../api';
 
 /**
  * Ensures the two-way binding syntax is correct.
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/extended/test/template_checks/invalid_banana_in_box/spec.ts b/packages/compiler-cli/src/ngtsc/typecheck/extended/test/template_checks/invalid_banana_in_box/spec.ts
index 4561fd166a8..2efe65b6ea0 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/extended/test/template_checks/invalid_banana_in_box/spec.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/extended/test/template_checks/invalid_banana_in_box/spec.ts
@@ -12,7 +12,7 @@ import {absoluteFrom, getSourceFileOrError} from '../../../../../file_system';
 import {runInEachFileSystem} from '../../../../../file_system/testing';
 import {getSourceCodeForDiagnostic} from '../../../../../testing';
 import {getClass, setup} from '../../../../testing';
-import {getExtendedTemplateDiagnosticsForComponent} from '../../../src/template_checker';
+import {ExtendedTemplateCheckerImpl} from '../../../src/extended_template_checker';
 import {InvalidBananaInBoxCheck} from '../../../src/template_checks/invalid_banana_in_box/index';
 
 runInEachFileSystem(() => {
@@ -22,19 +22,19 @@ runInEachFileSystem(() => {
       const {program, templateTypeChecker} = setup([{
         fileName,
         templates: {
-          'TestCmp': '<div ([input])="var1"> </div>',
+          'TestCmp': '<div ([notARealThing])="var1"> </div>',
         },
         source: 'export class TestCmp { var1: string = "text"; }'
       }]);
       const sf = getSourceFileOrError(program, fileName);
       const component = getClass(sf, 'TestCmp');
-      const diags = getExtendedTemplateDiagnosticsForComponent(
-          component, templateTypeChecker, program.getTypeChecker(),
-          [new InvalidBananaInBoxCheck()]);
+      const extendedTemplateChecker = new ExtendedTemplateCheckerImpl(
+          templateTypeChecker, program.getTypeChecker(), [new InvalidBananaInBoxCheck()]);
+      const diags = extendedTemplateChecker.getExtendedTemplateDiagnosticsForComponent(component);
       expect(diags.length).toBe(1);
       expect(diags[0].category).toBe(ts.DiagnosticCategory.Warning);
       expect(diags[0].code).toBe(ErrorCode.INVALID_BANANA_IN_BOX);
-      expect(getSourceCodeForDiagnostic(diags[0])).toBe('([input])="var1"');
+      expect(getSourceCodeForDiagnostic(diags[0])).toBe('([notARealThing])="var1"');
     });
 
     it('should not produce invalid banana in a box warning if written correctly', () => {
@@ -42,15 +42,15 @@ runInEachFileSystem(() => {
       const {program, templateTypeChecker} = setup([{
         fileName,
         templates: {
-          'TestCmp': '<div [(input)]="var1"> </div>',
+          'TestCmp': '<div [(notARealThing)]="var1"> </div>',
         },
         source: 'export class TestCmp { var1: string = "text"; }'
       }]);
       const sf = getSourceFileOrError(program, fileName);
       const component = getClass(sf, 'TestCmp');
-      const diags = getExtendedTemplateDiagnosticsForComponent(
-          component, templateTypeChecker, program.getTypeChecker(),
-          [new InvalidBananaInBoxCheck()]);
+      const extendedTemplateChecker = new ExtendedTemplateCheckerImpl(
+          templateTypeChecker, program.getTypeChecker(), [new InvalidBananaInBoxCheck()]);
+      const diags = extendedTemplateChecker.getExtendedTemplateDiagnosticsForComponent(component);
       expect(diags.length).toBe(0);
     });
 
@@ -60,15 +60,16 @@ runInEachFileSystem(() => {
          const {program, templateTypeChecker} = setup([{
            fileName,
            templates: {
-             'TestCmp': '<div (abc[123]def)="var1"> </div>',
+             'TestCmp': '<div (not[AReal]Thing)="var1"> </div>',
            },
            source: 'export class TestCmp { var1: string = "text"; }'
          }]);
          const sf = getSourceFileOrError(program, fileName);
          const component = getClass(sf, 'TestCmp');
-         const diags = getExtendedTemplateDiagnosticsForComponent(
-             component, templateTypeChecker, program.getTypeChecker(),
-             [new InvalidBananaInBoxCheck()]);
+         const extendedTemplateChecker = new ExtendedTemplateCheckerImpl(
+             templateTypeChecker, program.getTypeChecker(), [new InvalidBananaInBoxCheck()]);
+         const diags =
+             extendedTemplateChecker.getExtendedTemplateDiagnosticsForComponent(component);
          expect(diags.length).toBe(0);
        });
 
@@ -78,8 +79,8 @@ runInEachFileSystem(() => {
         fileName,
         templates: {
           'TestCmp': `<div> 
-             <div *ngIf="false" ([foo])="var1"> </div>
-             <ng-template #elseBlock ([bar])="var1">Content to render when condition is false.</ng-template>
+             <div *ngIf="false" ([notARealThing])="var1"> </div>
+             <ng-template #elseBlock ([notARealThing2])="var1">Content to render when condition is false.</ng-template>
            </div>`,
         },
         source: `export class TestCmp { 
@@ -88,16 +89,16 @@ runInEachFileSystem(() => {
       }]);
       const sf = getSourceFileOrError(program, fileName);
       const component = getClass(sf, 'TestCmp');
-      const diags = getExtendedTemplateDiagnosticsForComponent(
-          component, templateTypeChecker, program.getTypeChecker(),
-          [new InvalidBananaInBoxCheck()]);
+      const extendedTemplateChecker = new ExtendedTemplateCheckerImpl(
+          templateTypeChecker, program.getTypeChecker(), [new InvalidBananaInBoxCheck()]);
+      const diags = extendedTemplateChecker.getExtendedTemplateDiagnosticsForComponent(component);
       expect(diags.length).toBe(2);
       expect(diags[0].category).toBe(ts.DiagnosticCategory.Warning);
       expect(diags[0].code).toBe(ErrorCode.INVALID_BANANA_IN_BOX);
-      expect(getSourceCodeForDiagnostic(diags[0])).toBe('([foo])="var1"');
+      expect(getSourceCodeForDiagnostic(diags[0])).toBe('([notARealThing])="var1"');
       expect(diags[1].category).toBe(ts.DiagnosticCategory.Warning);
       expect(diags[1].code).toBe(ErrorCode.INVALID_BANANA_IN_BOX);
-      expect(getSourceCodeForDiagnostic(diags[1])).toBe('([bar])="var1"');
+      expect(getSourceCodeForDiagnostic(diags[1])).toBe('([notARealThing2])="var1"');
     });
   });
 });