diff --git a/aio/tools/transforms/angular-api-package/processors/mergeDecoratorDocs.js b/aio/tools/transforms/angular-api-package/processors/mergeDecoratorDocs.js
index 414e742b62..3ee25a8cb0 100644
--- a/aio/tools/transforms/angular-api-package/processors/mergeDecoratorDocs.js
+++ b/aio/tools/transforms/angular-api-package/processors/mergeDecoratorDocs.js
@@ -56,7 +56,6 @@ module.exports = function mergeDecoratorDocs(log) {
       {type: 'Param', description: 'parameter', functionName: 'makeParamDecorator'},
     ],
     $process(docs) {
-
       const decoratorDocs = Object.create(null);
 
       // find all the decorators, signified by a call to `make...Decorator<Decorator>(metadata)`
@@ -69,7 +68,8 @@ module.exports = function mergeDecoratorDocs(log) {
               // For example the `X` of `createDecorator<X>(...)`.
               const decoratorType = initializer.arguments[0].text;
 
-              log.debug('mergeDecoratorDocs: found decorator', doc.docType, doc.name, decoratorType);
+              log.debug(
+                  'mergeDecoratorDocs: found decorator', doc.docType, doc.name, decoratorType);
 
               doc.docType = 'decorator';
               doc.decoratorLocation = call.description;
@@ -84,8 +84,8 @@ module.exports = function mergeDecoratorDocs(log) {
       // merge the info from the associated metadata interfaces into the decorator docs
       docs = docs.filter(doc => {
         if (decoratorDocs[doc.name]) {
-
-          // We have found an `XxxDecorator` document that will hold the call signature of the decorator
+          // We have found an `XxxDecorator` document that will hold the call signature of the
+          // decorator
           var decoratorDoc = decoratorDocs[doc.name];
           var callMember = doc.members.find(member => member.isCallMember);
 
@@ -109,18 +109,44 @@ module.exports = function mergeDecoratorDocs(log) {
 };
 
 function getInitializer(doc) {
-  var initializer = doc.symbol && doc.symbol.valueDeclaration && doc.symbol.valueDeclaration.initializer;
+  const declaration = doc.symbol && doc.symbol.valueDeclaration;
+  if (!declaration || !declaration.initializer || !declaration.initializer.expression) {
+    return;
+  }
+
+  let initializer = declaration.initializer;
+
   // There appear to be two forms of initializer:
-  //    export var Injectable: InjectableFactory =
-  //    <InjectableFactory>makeDecorator(InjectableMetadata);
+  //
+  // ```
+  // export const Injectable: InjectableFactory =
+  //       <InjectableFactory>makeDecorator(InjectableMetadata);
+  // ```
+  //
   // and
-  //    export var RouteConfig: (configs: RouteDefinition[]) => ClassDecorator =
-  //    makeDecorator(RouteConfigAnnotation);
-  // In the first case, the type assertion `<InjectableFactory>` causes the AST to contain an
-  // extra level of expression
-  // to hold the new type of the expression.
-  if (initializer && initializer.expression && initializer.expression.expression) {
+  //
+  // ```
+  // export const RouteConfig: (configs: RouteDefinition[]) => ClassDecorator =
+  //       makeDecorator(RouteConfigAnnotation);
+  // ```
+  //
+  // In the first case, the type assertion `<InjectableFactory>` causes the AST to contain an extra
+  // level of expression to hold the new type of the expression.
+  if (initializer.type && initializer.expression.expression) {
     initializer = initializer.expression;
   }
+
+  // It is also possible that the decorator call is wrapped in a call to `attachInjectFlag()`:
+  //
+  // ```
+  // const Optional: OptionalDecorator =
+  //       attachInjectFlag(makeParamDecorator('Optional'), InternalInjectFlags.Optional);
+  // ```
+  //
+  // If so, use the first argument of the call.
+  if (initializer.arguments && initializer.expression.text === 'attachInjectFlag') {
+    initializer = initializer.arguments[0];
+  }
+
   return initializer;
 }
diff --git a/aio/tools/transforms/angular-api-package/processors/mergeDecoratorDocs.spec.js b/aio/tools/transforms/angular-api-package/processors/mergeDecoratorDocs.spec.js
index 77bc9f8141..9940fb9d9e 100644
--- a/aio/tools/transforms/angular-api-package/processors/mergeDecoratorDocs.spec.js
+++ b/aio/tools/transforms/angular-api-package/processors/mergeDecoratorDocs.spec.js
@@ -1,5 +1,5 @@
-var testPackage = require('../../helpers/test-package');
-var Dgeni = require('dgeni');
+const testPackage = require('../../helpers/test-package');
+const Dgeni = require('dgeni');
 
 describe('mergeDecoratorDocs processor', () => {
   let processor, moduleDoc, decoratorDoc, metadataDoc, otherDoc;
@@ -20,11 +20,10 @@ describe('mergeDecoratorDocs processor', () => {
       shortDescription: 'decorator - short description',
       description: 'decorator - description',
       symbol: {
-        valueDeclaration: { initializer: { expression: { text: 'makeDecorator' }, arguments: [{ text: 'X' }] } }
+        valueDeclaration:
+            {initializer: {expression: {text: 'makeDecorator'}, arguments: [{text: 'X'}]}}
       },
-      members: [
-        { name: 'templateUrl', description: 'templateUrl - description' }
-      ],
+      members: [{name: 'templateUrl', description: 'templateUrl - description'}],
       moduleDoc
     };
 
@@ -38,9 +37,7 @@ describe('mergeDecoratorDocs processor', () => {
           description: 'call interface - call member - description',
           usageNotes: 'call interface - call member - usageNotes',
         },
-        {
-          description: 'call interface - non call member - description'
-        }
+        {description: 'call interface - non call member - description'}
       ],
       moduleDoc
     };
@@ -49,7 +46,8 @@ describe('mergeDecoratorDocs processor', () => {
       name: 'Y',
       docType: 'const',
       symbol: {
-        valueDeclaration: { initializer: { expression: { text: 'otherCall' }, arguments: [{ text: 'param1' }] } }
+        valueDeclaration:
+            {initializer: {expression: {text: 'otherCall'}, arguments: [{text: 'param1'}]}}
       },
       moduleDoc
     };
@@ -58,11 +56,12 @@ describe('mergeDecoratorDocs processor', () => {
   });
 
 
-  it('should change the docType of only the docs that are initialized by a call to makeDecorator', () => {
-    processor.$process([decoratorDoc, metadataDoc, otherDoc]);
-    expect(decoratorDoc.docType).toEqual('decorator');
-    expect(otherDoc.docType).toEqual('const');
-  });
+  it('should change the docType of only the docs that are initialized by a call to makeDecorator',
+     () => {
+       processor.$process([decoratorDoc, metadataDoc, otherDoc]);
+       expect(decoratorDoc.docType).toEqual('decorator');
+       expect(otherDoc.docType).toEqual('const');
+     });
 
   it('should extract the "type" of the decorator meta data', () => {
     processor.$process([decoratorDoc, metadataDoc, otherDoc]);
@@ -88,4 +87,23 @@ describe('mergeDecoratorDocs processor', () => {
     processor.$process([decoratorDoc, metadataDoc, otherDoc]);
     expect(decoratorDoc.docType).toEqual('decorator');
   });
+
+  it('should handle a type cast before the "make decorator" call', () => {
+    decoratorDoc.symbol.valueDeclaration.initializer = {
+      expression: decoratorDoc.symbol.valueDeclaration.initializer,
+      type: {},
+    };
+    processor.$process([decoratorDoc, metadataDoc, otherDoc]);
+    expect(decoratorDoc.docType).toEqual('decorator');
+  });
+
+  it('should handle the "make decorator" call being wrapped in a call to `attachInjectFlag()`',
+     () => {
+       decoratorDoc.symbol.valueDeclaration.initializer = {
+         expression: {text: 'attachInjectFlag'},
+         arguments: [decoratorDoc.symbol.valueDeclaration.initializer]
+       };
+       processor.$process([decoratorDoc, metadataDoc, otherDoc]);
+       expect(decoratorDoc.docType).toEqual('decorator');
+     });
 });