feat: clean empty arrays and objects from the task def file (#52)

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Author: clareliguori

index.js

@@ -64,16 +64,43 @@ function findAppSpecKey(obj, keyName) {
   throw new Error(`AppSpec file must include property '${keyName}'`);
 }
 
-function undefinedOrNullReplacer(_, value) {
-  if (value === null || value === undefined) {
+function isEmptyValue(value) {
+  if (value === null || value === undefined || value === '') {
+    return true;
+  }
+
+  if (Array.isArray(value) && value.length === 0) {
+    return true;
+  }
+
+  if (typeof value === 'object' && Object.values(value).length === 0) {
+    return true;
+  }
+
+  return false;
+}
+
+function emptyValueReplacer(_, value) {
+  if (isEmptyValue(value)) {
+    return undefined;
+  }
+
+  if (typeof value === 'object') {
+    for (var childValue of Object.values(value)) {
+      if (!isEmptyValue(childValue)) {
+        // the object has at least one non-empty property
+        return value;
+      }
+    }
+    // the object has no non-empty property
     return undefined;
   }
 
   return value;
 }
 
 function cleanNullKeys(obj) {
-  return JSON.parse(JSON.stringify(obj, undefinedOrNullReplacer));
+  return JSON.parse(JSON.stringify(obj, emptyValueReplacer));
 }
 
 function removeIgnoredAttributes(taskDef) {

index.test.js

@@ -174,6 +174,44 @@ describe('Deploy to ECS', () => {
         expect(mockEcsRegisterTaskDef).toHaveBeenNthCalledWith(1, { family: 'task-def-family'});
     });
 
+    test('cleans empty arrays out of the task definition contents', async () => {
+        fs.readFileSync.mockImplementation((pathInput, encoding) => {
+            if (encoding != 'utf8') {
+                throw new Error(`Wrong encoding ${encoding}`);
+            }
+
+            return '{ "tags": [], "family": "task-def-family" }';
+        });
+
+        await run();
+        expect(core.setFailed).toHaveBeenCalledTimes(0);
+        expect(mockEcsRegisterTaskDef).toHaveBeenNthCalledWith(1, { family: 'task-def-family'});
+    });
+
+    test('cleans empty strings and objects out of the task definition contents', async () => {
+        fs.readFileSync.mockImplementation((pathInput, encoding) => {
+            if (encoding != 'utf8') {
+                throw new Error(`Wrong encoding ${encoding}`);
+            }
+
+            return '{ "memory": "", "containerDefinitions": [ { "name": "sample-container", "logConfiguration": {}, "repositoryCredentials": { "credentialsParameter": "" }, "cpu": 0, "essential": false } ], "requiresCompatibilities": [ "EC2" ], "family": "task-def-family" }';
+        });
+
+        await run();
+        expect(core.setFailed).toHaveBeenCalledTimes(0);
+        expect(mockEcsRegisterTaskDef).toHaveBeenNthCalledWith(1, {
+            family: 'task-def-family',
+            containerDefinitions: [
+                {
+                    name: 'sample-container',
+                    cpu: 0,
+                    essential: false
+                }
+            ],
+            requiresCompatibilities: [ 'EC2' ]
+        });
+    });
+
     test('cleans invalid keys out of the task definition contents', async () => {
         fs.readFileSync.mockImplementation((pathInput, encoding) => {
             if (encoding != 'utf8') {