fix: syntheticDefaultExportPolyfill Check if frozen before attempting to defineProperty. (#1235)

troynt · nchanged · commit 2c971e78bb1b · 2018-04-28T18:56:12.000+02:00
* fix: syntheticDefaultExportPolyfill Check if frozen before attempting to defineProperty.

* fix: LoaderAPI syntheticDefaultExportPolyfill should match fuse-box-responsive-api/index.js
diff --git a/modules/fuse-box-responsive-api/index.js b/modules/fuse-box-responsive-api/index.js
@@ -8,10 +8,27 @@
     /* @end */
 
     /* @if allowSyntheticDefaultImports */
-    function syntheticDefaultExportPolyfill(input){
-        return input !== null && ['function', 'object', 'array']
-            .indexOf(typeof input) > -1 && input.default === undefined ?
-                 Object.isFrozen(input) ? input.default = input : Object.defineProperty(input, "default", {value : input, writable : true, enumerable : false}) : void 0;
+    // NOTE: Should match syntheticDefaultExportPolyfill in LoaderAPI.ts
+    function syntheticDefaultExportPolyfill(input) {
+        if( input === null ||
+            ['function', 'object', 'array'].indexOf(typeof input) === -1 ||
+            input.hasOwnProperty("default") // use hasOwnProperty to avoid triggering usage warnings from libraries like mobx
+        ) {
+            return
+        }
+
+        // to get around frozen input
+        if (Object.isFrozen(input) ) {
+            input.default = input;
+            return;
+        }
+
+        // free to define properties
+        Object.defineProperty(input, "default", {
+            value: input,
+            writable: true,
+            enumerable: false
+        });
     }
     /* @end */
 
@@ -256,7 +273,7 @@
                 /* @if server */
                 var path = bMapping.c.s;
                 /* @end */
-                
+
                 /* @if browser */
                 var path = bMapping.c.b;
                 /* @end */
@@ -385,4 +402,4 @@
 
     /* @if !isContained */
 })();
-/* @end */
+/* @end */
diff --git a/src/loader/LoaderAPI.ts b/src/loader/LoaderAPI.ts
@@ -395,10 +395,27 @@ function $trigger(name: string, args: any) {
     }
 };
 
+// NOTE: Should match syntheticDefaultExportPolyfill in fuse-box-responsive-api/index.js
 function syntheticDefaultExportPolyfill(input){
-    return input !== null && ['function', 'object', 'array']
-        .indexOf(typeof input) > -1 && input.default === undefined ?
-             Object.isFrozen(input) ? input.default = input : Object.defineProperty(input, "default", {value : input, writable : true, enumerable : false}) : void 0;
+    if( input === null ||
+        ['function', 'object', 'array'].indexOf(typeof input) === -1 ||
+        input.hasOwnProperty("default") // use hasOwnProperty to avoid triggering usage warnings from libraries like mobx
+    ) {
+        return
+    }
+
+    // to get around frozen input
+    if (Object.isFrozen(input) ) {
+        input.default = input;
+        return;
+    }
+
+    // free to define properties
+    Object.defineProperty(input, "default", {
+        value: input,
+        writable: true,
+        enumerable: false
+    });
 }
 
 /**
