diff --git a/packages/compiler-cli/ngcc/src/host/esm5_host.ts b/packages/compiler-cli/ngcc/src/host/esm5_host.ts
index 67c7abb291..17fd2134c8 100644
--- a/packages/compiler-cli/ngcc/src/host/esm5_host.ts
+++ b/packages/compiler-cli/ngcc/src/host/esm5_host.ts
@@ -9,7 +9,7 @@
 import * as ts from 'typescript';
 
 import {ClassDeclaration, ClassMember, ClassMemberKind, Declaration, Decorator, FunctionDefinition, isNamedVariableDeclaration, Parameter, reflectObjectLiteral} from '../../../src/ngtsc/reflection';
-import {getNameText, getTsHelperFnFromDeclaration, hasNameIdentifier} from '../utils';
+import {getNameText, getTsHelperFnFromDeclaration, getTsHelperFnFromIdentifier, hasNameIdentifier} from '../utils';
 
 import {Esm2015ReflectionHost, getPropertyValueFromSymbol, isAssignment, isAssignmentStatement, ParamInfo} from './esm2015_host';
 import {NgccClassSymbol} from './ngcc_host';
@@ -192,6 +192,22 @@ export class Esm5ReflectionHost extends Esm2015ReflectionHost {
   getDeclarationOfIdentifier(id: ts.Identifier): Declaration|null {
     const superDeclaration = super.getDeclarationOfIdentifier(id);
 
+    if (superDeclaration === null) {
+      const nonEmittedNorImportedTsHelperDeclaration = getTsHelperFnFromIdentifier(id);
+      if (nonEmittedNorImportedTsHelperDeclaration !== null) {
+        // No declaration could be found for this identifier and its name matches a known TS helper
+        // function. This can happen if a package is compiled with `noEmitHelpers: true` and
+        // `importHelpers: false` (the default). This is, for example, the case with
+        // `@nativescript/angular@9.0.0-next-2019-11-12-155500-01`.
+        return {
+          expression: id,
+          known: nonEmittedNorImportedTsHelperDeclaration,
+          node: null,
+          viaModule: null,
+        };
+      }
+    }
+
     if (superDeclaration === null || superDeclaration.node === null ||
         superDeclaration.known !== null) {
       return superDeclaration;
diff --git a/packages/compiler-cli/ngcc/test/host/commonjs_host_spec.ts b/packages/compiler-cli/ngcc/test/host/commonjs_host_spec.ts
index 421bab1b0d..b4a4231371 100644
--- a/packages/compiler-cli/ngcc/test/host/commonjs_host_spec.ts
+++ b/packages/compiler-cli/ngcc/test/host/commonjs_host_spec.ts
@@ -2000,6 +2000,74 @@ exports.ExternalModule = ExternalModule;
           testForHelper('b', '__spread', KnownDeclaration.TsHelperSpread, 'tslib');
           testForHelper('c', '__spreadArrays', KnownDeclaration.TsHelperSpreadArrays, 'tslib');
         });
+
+        it('should recognize undeclared, unimported TypeScript helpers (by name)', () => {
+          const file: TestFile = {
+            name: _('/test.js'),
+            contents: `
+              var a = __assign({foo: 'bar'}, {baz: 'qux'});
+              var b = __spread(['foo', 'bar'], ['baz', 'qux']);
+              var c = __spreadArrays(['foo', 'bar'], ['baz', 'qux']);
+            `,
+          };
+          loadTestFiles([file]);
+          const bundle = makeTestBundleProgram(file.name);
+          const host =
+              createHost(bundle, new CommonJsReflectionHost(new MockLogger(), false, bundle));
+
+          const testForHelper =
+              (varName: string, helperName: string, knownAs: KnownDeclaration) => {
+                const node =
+                    getDeclaration(bundle.program, file.name, varName, ts.isVariableDeclaration);
+                const helperIdentifier = getIdentifierFromCallExpression(node);
+                const helperDeclaration = host.getDeclarationOfIdentifier(helperIdentifier);
+
+                expect(helperDeclaration).toEqual({
+                  known: knownAs,
+                  expression: helperIdentifier,
+                  node: null,
+                  viaModule: null,
+                });
+              };
+
+          testForHelper('a', '__assign', KnownDeclaration.TsHelperAssign);
+          testForHelper('b', '__spread', KnownDeclaration.TsHelperSpread);
+          testForHelper('c', '__spreadArrays', KnownDeclaration.TsHelperSpreadArrays);
+        });
+
+        it('should recognize suffixed, undeclared, unimported TypeScript helpers (by name)', () => {
+          const file: TestFile = {
+            name: _('/test.js'),
+            contents: `
+              var a = __assign$1({foo: 'bar'}, {baz: 'qux'});
+              var b = __spread$2(['foo', 'bar'], ['baz', 'qux']);
+              var c = __spreadArrays$3(['foo', 'bar'], ['baz', 'qux']);
+            `,
+          };
+          loadTestFiles([file]);
+          const bundle = makeTestBundleProgram(file.name);
+          const host =
+              createHost(bundle, new CommonJsReflectionHost(new MockLogger(), false, bundle));
+
+          const testForHelper =
+              (varName: string, helperName: string, knownAs: KnownDeclaration) => {
+                const node =
+                    getDeclaration(bundle.program, file.name, varName, ts.isVariableDeclaration);
+                const helperIdentifier = getIdentifierFromCallExpression(node);
+                const helperDeclaration = host.getDeclarationOfIdentifier(helperIdentifier);
+
+                expect(helperDeclaration).toEqual({
+                  known: knownAs,
+                  expression: helperIdentifier,
+                  node: null,
+                  viaModule: null,
+                });
+              };
+
+          testForHelper('a', '__assign$1', KnownDeclaration.TsHelperAssign);
+          testForHelper('b', '__spread$2', KnownDeclaration.TsHelperSpread);
+          testForHelper('c', '__spreadArrays$3', KnownDeclaration.TsHelperSpreadArrays);
+        });
       });
 
       describe('getExportsOfModule()', () => {
diff --git a/packages/compiler-cli/ngcc/test/host/esm5_host_spec.ts b/packages/compiler-cli/ngcc/test/host/esm5_host_spec.ts
index 8182a8807d..0f5190a3c2 100644
--- a/packages/compiler-cli/ngcc/test/host/esm5_host_spec.ts
+++ b/packages/compiler-cli/ngcc/test/host/esm5_host_spec.ts
@@ -2124,6 +2124,68 @@ runInEachFileSystem(() => {
         testForHelper('b', '__spread', KnownDeclaration.TsHelperSpread, 'tslib');
         testForHelper('c', '__spreadArrays', KnownDeclaration.TsHelperSpreadArrays, 'tslib');
       });
+
+      it('should recognize undeclared, unimported TypeScript helpers (by name)', () => {
+        const file: TestFile = {
+          name: _('/test.js'),
+          contents: `
+            var a = __assign({foo: 'bar'}, {baz: 'qux'});
+            var b = __spread(['foo', 'bar'], ['baz', 'qux']);
+            var c = __spreadArrays(['foo', 'bar'], ['baz', 'qux']);
+          `,
+        };
+        loadTestFiles([file]);
+        const bundle = makeTestBundleProgram(file.name);
+        const host = createHost(bundle, new Esm5ReflectionHost(new MockLogger(), false, bundle));
+
+        const testForHelper = (varName: string, helperName: string, knownAs: KnownDeclaration) => {
+          const node = getDeclaration(bundle.program, file.name, varName, ts.isVariableDeclaration);
+          const helperIdentifier = getIdentifierFromCallExpression(node);
+          const helperDeclaration = host.getDeclarationOfIdentifier(helperIdentifier);
+
+          expect(helperDeclaration).toEqual({
+            known: knownAs,
+            expression: helperIdentifier,
+            node: null,
+            viaModule: null,
+          });
+        };
+
+        testForHelper('a', '__assign', KnownDeclaration.TsHelperAssign);
+        testForHelper('b', '__spread', KnownDeclaration.TsHelperSpread);
+        testForHelper('c', '__spreadArrays', KnownDeclaration.TsHelperSpreadArrays);
+      });
+
+      it('should recognize suffixed, undeclared, unimported TypeScript helpers (by name)', () => {
+        const file: TestFile = {
+          name: _('/test.js'),
+          contents: `
+            var a = __assign$1({foo: 'bar'}, {baz: 'qux'});
+            var b = __spread$2(['foo', 'bar'], ['baz', 'qux']);
+            var c = __spreadArrays$3(['foo', 'bar'], ['baz', 'qux']);
+          `,
+        };
+        loadTestFiles([file]);
+        const bundle = makeTestBundleProgram(file.name);
+        const host = createHost(bundle, new Esm5ReflectionHost(new MockLogger(), false, bundle));
+
+        const testForHelper = (varName: string, helperName: string, knownAs: KnownDeclaration) => {
+          const node = getDeclaration(bundle.program, file.name, varName, ts.isVariableDeclaration);
+          const helperIdentifier = getIdentifierFromCallExpression(node);
+          const helperDeclaration = host.getDeclarationOfIdentifier(helperIdentifier);
+
+          expect(helperDeclaration).toEqual({
+            known: knownAs,
+            expression: helperIdentifier,
+            node: null,
+            viaModule: null,
+          });
+        };
+
+        testForHelper('a', '__assign$1', KnownDeclaration.TsHelperAssign);
+        testForHelper('b', '__spread$2', KnownDeclaration.TsHelperSpread);
+        testForHelper('c', '__spreadArrays$3', KnownDeclaration.TsHelperSpreadArrays);
+      });
     });
 
     describe('getExportsOfModule()', () => {
diff --git a/packages/compiler-cli/ngcc/test/host/umd_host_spec.ts b/packages/compiler-cli/ngcc/test/host/umd_host_spec.ts
index 89319ab05f..5aea2a1f13 100644
--- a/packages/compiler-cli/ngcc/test/host/umd_host_spec.ts
+++ b/packages/compiler-cli/ngcc/test/host/umd_host_spec.ts
@@ -2101,6 +2101,84 @@ runInEachFileSystem(() => {
         testForHelper('b', '__spread', KnownDeclaration.TsHelperSpread, 'tslib');
         testForHelper('c', '__spreadArrays', KnownDeclaration.TsHelperSpreadArrays, 'tslib');
       });
+
+      it('should recognize undeclared, unimported TypeScript helpers (by name)', () => {
+        const file: TestFile = {
+          name: _('/test.js'),
+          contents: `
+            (function (global, factory) {
+              typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
+              typeof define === 'function' && define.amd ? define('test', ['exports'], factory) :
+              (factory(global.test));
+            }(this, (function (exports) { 'use strict';
+              var a = __assign({foo: 'bar'}, {baz: 'qux'});
+              var b = __spread(['foo', 'bar'], ['baz', 'qux']);
+              var c = __spreadArrays(['foo', 'bar'], ['baz', 'qux']);
+            })));
+          `,
+        };
+        loadTestFiles([file]);
+        const bundle = makeTestBundleProgram(file.name);
+        const host = createHost(bundle, new UmdReflectionHost(new MockLogger(), false, bundle));
+        const {factoryFn} = parseStatementForUmdModule(
+            getSourceFileOrError(bundle.program, file.name).statements[0])!;
+
+        const testForHelper = (varName: string, helperName: string, knownAs: KnownDeclaration) => {
+          const node = getVariableDeclaration(factoryFn, varName);
+          const helperIdentifier = getIdentifierFromCallExpression(node);
+          const helperDeclaration = host.getDeclarationOfIdentifier(helperIdentifier);
+
+          expect(helperDeclaration).toEqual({
+            known: knownAs,
+            expression: helperIdentifier,
+            node: null,
+            viaModule: null,
+          });
+        };
+
+        testForHelper('a', '__assign', KnownDeclaration.TsHelperAssign);
+        testForHelper('b', '__spread', KnownDeclaration.TsHelperSpread);
+        testForHelper('c', '__spreadArrays', KnownDeclaration.TsHelperSpreadArrays);
+      });
+
+      it('should recognize suffixed, undeclared, unimported TypeScript helpers (by name)', () => {
+        const file: TestFile = {
+          name: _('/test.js'),
+          contents: `
+            (function (global, factory) {
+              typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
+              typeof define === 'function' && define.amd ? define('test', ['exports'], factory) :
+              (factory(global.test));
+            }(this, (function (exports) { 'use strict';
+              var a = __assign$1({foo: 'bar'}, {baz: 'qux'});
+              var b = __spread$2(['foo', 'bar'], ['baz', 'qux']);
+              var c = __spreadArrays$3(['foo', 'bar'], ['baz', 'qux']);
+            })));
+          `,
+        };
+        loadTestFiles([file]);
+        const bundle = makeTestBundleProgram(file.name);
+        const host = createHost(bundle, new UmdReflectionHost(new MockLogger(), false, bundle));
+        const {factoryFn} = parseStatementForUmdModule(
+            getSourceFileOrError(bundle.program, file.name).statements[0])!;
+
+        const testForHelper = (varName: string, helperName: string, knownAs: KnownDeclaration) => {
+          const node = getVariableDeclaration(factoryFn, varName);
+          const helperIdentifier = getIdentifierFromCallExpression(node);
+          const helperDeclaration = host.getDeclarationOfIdentifier(helperIdentifier);
+
+          expect(helperDeclaration).toEqual({
+            known: knownAs,
+            expression: helperIdentifier,
+            node: null,
+            viaModule: null,
+          });
+        };
+
+        testForHelper('a', '__assign$1', KnownDeclaration.TsHelperAssign);
+        testForHelper('b', '__spread$2', KnownDeclaration.TsHelperSpread);
+        testForHelper('c', '__spreadArrays$3', KnownDeclaration.TsHelperSpreadArrays);
+      });
     });
 
     describe('getExportsOfModule()', () => {