diff --git a/packages/angular_devkit/build_optimizer/src/build-optimizer/build-optimizer_spec.ts b/packages/angular_devkit/build_optimizer/src/build-optimizer/build-optimizer_spec.ts
index 79d5b3808451..0b031cd041b2 100644
--- a/packages/angular_devkit/build_optimizer/src/build-optimizer/build-optimizer_spec.ts
+++ b/packages/angular_devkit/build_optimizer/src/build-optimizer/build-optimizer_spec.ts
@@ -63,7 +63,7 @@ describe('build-optimizer', () => {
           ChangeDetectionStrategy[ChangeDetectionStrategy["OnPush"] = 0] = "OnPush";
           ChangeDetectionStrategy[ChangeDetectionStrategy["Default"] = 1] = "Default";
           return ChangeDetectionStrategy;
-        })(ChangeDetectionStrategy || (ChangeDetectionStrategy = {}));
+        })({});
         var Clazz = /*@__PURE__*/ (function () { function Clazz() { } ${staticProperty} return Clazz; }());
         var ComponentClazz = /*@__PURE__*/ (function () {
           function ComponentClazz() { }
diff --git a/packages/angular_devkit/build_optimizer/src/transforms/wrap-enums.ts b/packages/angular_devkit/build_optimizer/src/transforms/wrap-enums.ts
index 76231cd27eca..0100b162aab4 100644
--- a/packages/angular_devkit/build_optimizer/src/transforms/wrap-enums.ts
+++ b/packages/angular_devkit/build_optimizer/src/transforms/wrap-enums.ts
@@ -94,7 +94,8 @@ function visitBlockStatements(
             // update IIFE and replace variable statement and old IIFE
             updatedStatements.splice(uIndex, 2, updateEnumIife(
               currentStatement,
-              iife,
+              iife[0],
+              iife[1],
             ));
             // skip IIFE statement
             oIndex++;
@@ -158,7 +159,10 @@ function visitBlockStatements(
 }
 
 // TS 2.3 enums have statements that are inside a IIFE.
-function findTs2_3EnumIife(name: string, statement: ts.Statement): ts.CallExpression | null {
+function findTs2_3EnumIife(
+  name: string,
+  statement: ts.Statement,
+): [ts.CallExpression, ts.Expression | undefined] | null {
   if (!ts.isExpressionStatement(statement)) {
     return null;
   }
@@ -173,6 +177,7 @@ function findTs2_3EnumIife(name: string, statement: ts.Statement): ts.CallExpres
   }
 
   const callExpression = expression;
+  let exportExpression;
 
   let argument = expression.arguments[0];
   if (!ts.isBinaryExpression(argument)) {
@@ -183,12 +188,14 @@ function findTs2_3EnumIife(name: string, statement: ts.Statement): ts.CallExpres
     return null;
   }
 
+  let potentialExport = false;
   if (argument.operatorToken.kind === ts.SyntaxKind.FirstAssignment) {
     if (!ts.isBinaryExpression(argument.right)
         || argument.right.operatorToken.kind !== ts.SyntaxKind.BarBarToken) {
       return null;
     }
 
+    potentialExport = true;
     argument = argument.right;
   }
 
@@ -200,6 +207,10 @@ function findTs2_3EnumIife(name: string, statement: ts.Statement): ts.CallExpres
     return null;
   }
 
+  if (potentialExport && !ts.isIdentifier(argument.left)) {
+    exportExpression = argument.left;
+  }
+
   expression = expression.expression;
   while (ts.isParenthesizedExpression(expression)) {
     expression = expression.expression;
@@ -264,7 +275,7 @@ function findTs2_3EnumIife(name: string, statement: ts.Statement): ts.CallExpres
     }
   }
 
-  return callExpression;
+  return [callExpression, exportExpression];
 }
 
 // TS 2.2 enums have statements after the variable declaration, with index statements followed
@@ -362,9 +373,22 @@ function findEnumNameStatements(
   return enumStatements;
 }
 
-function updateHostNode(hostNode: ts.VariableStatement, expression: ts.Expression): ts.Statement {
+function addPureComment<T extends ts.Node>(node: T): T {
   const pureFunctionComment = '@__PURE__';
 
+  return ts.addSyntheticLeadingComment(
+    node,
+    ts.SyntaxKind.MultiLineCommentTrivia,
+    pureFunctionComment,
+    false,
+  );
+}
+
+function updateHostNode(
+  hostNode: ts.VariableStatement,
+  expression: ts.Expression,
+): ts.Statement {
+
   // Update existing host node with the pure comment before the variable declaration initializer.
   const variableDeclaration = hostNode.declarationList.declarations[0];
   const outerVarStmt = ts.updateVariableStatement(
@@ -377,12 +401,7 @@ function updateHostNode(hostNode: ts.VariableStatement, expression: ts.Expressio
           variableDeclaration,
           variableDeclaration.name,
           variableDeclaration.type,
-          ts.addSyntheticLeadingComment(
-            expression,
-            ts.SyntaxKind.MultiLineCommentTrivia,
-            pureFunctionComment,
-            false,
-          ),
+          expression,
         ),
       ],
     ),
@@ -391,12 +410,22 @@ function updateHostNode(hostNode: ts.VariableStatement, expression: ts.Expressio
   return outerVarStmt;
 }
 
-function updateEnumIife(hostNode: ts.VariableStatement, iife: ts.CallExpression): ts.Statement {
+function updateEnumIife(
+  hostNode: ts.VariableStatement,
+  iife: ts.CallExpression,
+  exportAssignment?: ts.Expression,
+): ts.Statement {
   if (!ts.isParenthesizedExpression(iife.expression)
       || !ts.isFunctionExpression(iife.expression.expression)) {
     throw new Error('Invalid IIFE Structure');
   }
 
+  // Ignore export assignment if variable is directly exported
+  if (hostNode.modifiers
+      && hostNode.modifiers.findIndex(m => m.kind == ts.SyntaxKind.ExportKeyword) != -1) {
+    exportAssignment = undefined;
+  }
+
   const expression = iife.expression.expression;
   const updatedFunction = ts.updateFunctionExpression(
     expression,
@@ -415,6 +444,10 @@ function updateEnumIife(hostNode: ts.VariableStatement, iife: ts.CallExpression)
     ),
   );
 
+  let arg: ts.Expression = ts.createObjectLiteral();
+  if (exportAssignment) {
+    arg = ts.createBinary(exportAssignment, ts.SyntaxKind.BarBarToken, arg);
+  }
   const updatedIife = ts.updateCall(
     iife,
     ts.updateParen(
@@ -422,10 +455,18 @@ function updateEnumIife(hostNode: ts.VariableStatement, iife: ts.CallExpression)
       updatedFunction,
     ),
     iife.typeArguments,
-    iife.arguments,
+    [arg],
   );
 
-  return updateHostNode(hostNode, updatedIife);
+  let value: ts.Expression = addPureComment(updatedIife);
+  if (exportAssignment) {
+    value = ts.createBinary(
+      exportAssignment,
+      ts.SyntaxKind.FirstAssignment,
+      updatedIife);
+  }
+
+  return updateHostNode(hostNode, value);
 }
 
 function createWrappedEnum(
@@ -450,5 +491,5 @@ function createWrappedEnum(
     innerReturn,
   ]);
 
-  return updateHostNode(hostNode, ts.createParen(iife));
+  return updateHostNode(hostNode, addPureComment(ts.createParen(iife)));
 }
diff --git a/packages/angular_devkit/build_optimizer/src/transforms/wrap-enums_spec.ts b/packages/angular_devkit/build_optimizer/src/transforms/wrap-enums_spec.ts
index 14ce356949cc..1718dfa7838a 100644
--- a/packages/angular_devkit/build_optimizer/src/transforms/wrap-enums_spec.ts
+++ b/packages/angular_devkit/build_optimizer/src/transforms/wrap-enums_spec.ts
@@ -50,7 +50,7 @@ describe('wrap-enums', () => {
         ChangeDetectionStrategy[ChangeDetectionStrategy["OnPush"] = 0] = "OnPush";
         ChangeDetectionStrategy[ChangeDetectionStrategy["Default"] = 1] = "Default";
         return ChangeDetectionStrategy;
-      })(ChangeDetectionStrategy || (ChangeDetectionStrategy = {}));
+      })({});
     `;
 
     expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
@@ -73,7 +73,7 @@ describe('wrap-enums', () => {
           AnimatorControlState[AnimatorControlState["FINISHED"] = 3] = "FINISHED";
           AnimatorControlState[AnimatorControlState["DESTROYED"] = 4] = "DESTROYED";
           return AnimatorControlState;
-      })(AnimatorControlState || (AnimatorControlState = {}));
+      })({});
     `;
 
     expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
@@ -155,7 +155,7 @@ describe('wrap-enums', () => {
           RequestMethod[RequestMethod["Head"] = 5] = "Head";
           RequestMethod[RequestMethod["Patch"] = 6] = "Patch";
           return RequestMethod;
-      })(RequestMethod || (RequestMethod = {}));
+      })({});
     `;
 
     expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
@@ -171,12 +171,12 @@ describe('wrap-enums', () => {
       })(ExportEnum = exports.ExportEnum || (exports.ExportEnum = {}));
     `;
     const output = tags.stripIndent`
-      var ExportEnum = /*@__PURE__*/ (function (ExportEnum) {
+      var ExportEnum = exports.ExportEnum = /*@__PURE__*/ (function (ExportEnum) {
         ExportEnum[ExportEnum["A"] = 0] = "A";
         ExportEnum[ExportEnum["B"] = 1] = "B";
         ExportEnum[ExportEnum["C"] = 2] = "C";
         return ExportEnum;
-      })(ExportEnum = exports.ExportEnum || (exports.ExportEnum = {}));
+      })(exports.ExportEnum || {});
     `;
 
     expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);