Adding flatten objects

src/objects/flatten.test.ts

@@ -0,0 +1,23 @@
+import flatten from './flatten';
+
+describe('flatten', () => {
+  it('flattens the given object', () => {
+    const nestedObject = {
+      hello: {
+        yes: 'true',
+      },
+      flat: 'yes',
+      nested: {
+        array: [1, 2],
+      },
+    };
+
+    const result = flatten(nestedObject);
+
+    expect(result).toEqual({
+      'hello.yes': 'true',
+      flat: 'yes',
+      'nested.array': [1, 2],
+    });
+  });
+});

src/objects/flatten.ts

@@ -0,0 +1,24 @@
+function _flatten<Result extends object>(
+  obj: Record<string, unknown>,
+  recursiveContext?: { parentKey: string; result: Result }
+): Result {
+  const initialResult = recursiveContext?.result ?? ({} as unknown as Result);
+  const parentKey = recursiveContext?.parentKey;
+
+  return Object.entries(obj).reduce<Result>((acc, [key, value]) => {
+    const newKey = parentKey != null ? `${parentKey}.${key}` : key;
+    if (typeof value !== 'object') return { ...acc, [newKey]: value };
+    if (Array.isArray(value)) return { ...acc, [newKey]: value };
+
+    return _flatten(value as Record<string, unknown>, {
+      parentKey: newKey,
+      result: acc,
+    });
+  }, initialResult);
+}
+
+function flatten<Result extends object>(obj: Record<string, unknown>): Result {
+  return _flatten(obj);
+}
+
+export default flatten;

src/objects/index.ts

@@ -1,2 +1,3 @@
 export * from './omit';
 export * from './omitBy';
+export * from './flatten';