Merge pull request #516 from alexzurbonsen/fix-mergeObjects-function

optimize merge defaults strategy

src/__tests__/unit/util/helpers.test.ts

@@ -7,8 +7,7 @@ jest.mock('../../../util/logger', () => ({
     error: mockError,
   },
 }));
-
-import {andHandle} from '../../../util/helpers';
+import {andHandle, mergeObjects} from '../../../util/helpers';
 import {ERRORS} from '../../../util/errors';
 
 const {WriteFileError} = ERRORS;
@@ -38,3 +37,142 @@ describe('util/helpers: ', () => {
     });
   });
 });
+
+describe('util/helpers: ', () => {
+  describe('mergeObjects(): ', () => {
+    it('does not override input.', () => {
+      expect.assertions(1);
+
+      const input = {
+        a: 1,
+        b: false,
+        c: 'testInput',
+      };
+
+      const defaults = {
+        c: 'testDefault',
+      };
+      const result = mergeObjects(defaults, input);
+
+      expect(result).toEqual(input);
+    });
+
+    it('overrides null/undefined inputs.', () => {
+      expect.assertions(1);
+
+      const input = {
+        a: 1,
+        b: false,
+        c: 'testInput',
+        d: null,
+        e: undefined,
+      };
+
+      const defaults = {
+        c: 'testDefault',
+        d: 'testDefault',
+        e: 'testDefault',
+      };
+      const result = mergeObjects(defaults, input);
+      const expectedResult = {
+        a: 1,
+        b: false,
+        c: 'testInput',
+        d: 'testDefault',
+        e: 'testDefault',
+      };
+
+      expect(result).toEqual(expectedResult);
+    });
+
+    it('adds only properties missing in input.', () => {
+      expect.assertions(1);
+
+      const input = {
+        a: 1,
+        b: false,
+        c: 'testInput',
+      };
+
+      const defaults = {
+        b: true,
+        c: 'testDefault',
+        d: 25,
+      };
+
+      const result = mergeObjects(defaults, input);
+      const expectedResult = {
+        a: 1,
+        b: false,
+        c: 'testInput',
+        d: 25,
+      };
+
+      expect(result).toEqual(expectedResult);
+    });
+
+    it('keeps values from input in case of nested objects.', () => {
+      expect.assertions(1);
+
+      const input = {
+        a: 1,
+        b: false,
+        c: 'testInput',
+        d: {
+          e: 1,
+        },
+      };
+
+      const defaults = {
+        b: true,
+        c: 'testDefault1',
+        d: {
+          e: 25,
+          f: 'testDefault2',
+        },
+      };
+
+      const result = mergeObjects(defaults, input);
+      const expectedResult = {
+        a: 1,
+        b: false,
+        c: 'testInput',
+        d: {
+          e: 1,
+        },
+      };
+
+      expect(result).toEqual(expectedResult);
+    });
+
+    it('keeps value from input in case of arrays.', () => {
+      expect.assertions(1);
+
+      const input = {
+        a: 1,
+        b: false,
+        c: 'testInput1',
+        d: [1, 2, 3, 4],
+        e: 'testInput2',
+      };
+
+      const defaults = {
+        b: true,
+        c: 'testDefault1',
+        d: [5, 6, 7, 8, 9],
+        e: [1, 2, 3],
+      };
+
+      const result = mergeObjects(defaults, input);
+      const expectedResult = {
+        a: 1,
+        b: false,
+        c: 'testInput1',
+        d: [1, 2, 3, 4],
+        e: 'testInput2',
+      };
+
+      expect(result).toEqual(expectedResult);
+    });
+  });
+});

src/lib/compute.ts

@@ -22,7 +22,7 @@ const mergeDefaults = (
 ) => {
   if (inputs) {
     const response = defaults
-      ? inputs.map(input => mergeObjects(input, defaults))
+      ? inputs.map(input => mergeObjects(defaults, input))
       : inputs;
 
     return response;

src/util/helpers.ts

@@ -1,6 +1,5 @@
-import {ERRORS} from './errors';
-
 import {STRINGS} from '../config';
+import {ERRORS} from './errors';
 import {logger} from './logger';
 
 const {ISSUE_TEMPLATE} = STRINGS;
@@ -19,22 +18,20 @@ export const andHandle = (error: Error) => {
 };
 
 /**
- * Mergers two objects, omitting null values.
+ * Append entries from defaults which are missing from inputs.
  */
-export const mergeObjects = (object1: any, object2: any) => {
-  const merged: Record<string, any> = {};
-
-  const keys1 = Object.keys(object1);
-  keys1.forEach(key1 => {
-    merged[key1] = object1[key1] || object2[key1];
-  });
-
-  const keys2 = Object.keys(object2);
-  keys2.forEach(key2 => {
-    if (!keys1.includes(key2)) {
-      merged[key2] = object2[key2];
+export const mergeObjects = (defaults: any, input: any) => {
+  const merged: Record<string, any> = structuredClone(input);
+
+  for (const key in defaults) {
+    if (!(key in input)) {
+      merged[key] = defaults[key];
     }
-  });
+
+    if (merged[key] === undefined || merged[key] === null) {
+      merged[key] = defaults[key];
+    }
+  }
 
   return merged;
 };