Prevent config.parse() output from being used as input (#134)

walmartlabs · Jun 13, 2020 · 7f50b46 · 7f50b46
1 parent 9a56bd5
commit 7f50b46
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Showing 2 changed files with 13 additions and 2 deletions.
diff --git a/packages/core/package.json b/packages/core/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@walmartlabs/cookie-cutter-core",
-    "version": "1.3.0-beta.4",
+    "version": "1.3.0-beta.5",
     "license": "Apache-2.0",
     "main": "dist/index.js",
     "types": "dist/index.d.ts",

diff --git a/packages/core/src/config.ts b/packages/core/src/config.ts
@@ -66,6 +66,13 @@ export function parse<T>(TRoot: IClassType<T>, actual: any, base?: Partial<T>):
         }
     }
 
+    if (isSection(actual)) {
+        throw new Error(
+            "The value of `actual` has no enumerable properties. Make sure the object being " +
+                "passed is not the output of `config.parse<T>()` (i.e. does not have the '@section' decorator)."
+        );
+    }
+
     const instance = new TRoot();
     if (verifyIsSection(instance)) {
         const config: T & ISection = new TRoot() as any;
@@ -303,8 +310,12 @@ interface ISection {
     readonly __extensible?: boolean;
 }
 
+function isSection(obj: any): obj is ISection {
+    return obj && obj.__assignedProperties;
+}
+
 function verifyIsSection(obj: any): obj is ISection {
-    if (obj && obj.__assignedProperties) {
+    if (isSection(obj)) {
         return true;
     }