feat(i18n): convert to opaque keys (#1848)

packages/utils/src/object/flatten.ts

@@ -0,0 +1,33 @@
+/**
+ * Flattens nested object values into dot-separated keys.
+ *
+ * @param object - The object to flatten.
+ * @param options - Options controlling the flattened key path.
+ * @returns A new object containing the flattened values.
+ *
+ * @example
+ * ```ts
+ * flatten({ buttons: { play: 'Play' } });
+ * // { 'buttons.play': 'Play' }
+ * ```
+ */
+export interface FlattenOptions {
+  prefix?: string;
+}
+
+export function flatten(object: Record<string, unknown>, options: FlattenOptions = {}): Record<string, unknown> {
+  const { prefix = '' } = options;
+  const result: Record<string, unknown> = {};
+
+  for (const [key, value] of Object.entries(object)) {
+    const fullKey = prefix ? `${prefix}.${key}` : key;
+
+    if (value !== null && typeof value === 'object' && !Array.isArray(value)) {
+      Object.assign(result, flatten(value as Record<string, unknown>, { prefix: fullKey }));
+    } else {
+      result[fullKey] = value;
+    }
+  }
+
+  return result;
+}

packages/utils/src/object/index.ts

@@ -1,5 +1,6 @@
 export { deepEqual } from './deep-equal';
 export { defaults } from './defaults';
+export { type FlattenOptions, flatten } from './flatten';
 export { omit } from './omit';
 export { pick } from './pick';
 export { shallowEqual } from './shallow-equal';

packages/utils/src/object/tests/flatten.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, it } from 'vitest';
+import { flatten } from '../flatten';
+
+describe('flatten', () => {
+  it('flattens nested objects into dot-separated keys', () => {
+    expect(
+      flatten({
+        buttons: { play: 'Play', pause: 'Pause' },
+        common: { empty: '' },
+      })
+    ).toEqual({
+      'buttons.play': 'Play',
+      'buttons.pause': 'Pause',
+      'common.empty': '',
+    });
+  });
+
+  it('preserves non-object values as leaves', () => {
+    expect(flatten({ value: 0, enabled: false, items: ['one'] })).toEqual({
+      value: 0,
+      enabled: false,
+      items: ['one'],
+    });
+  });
+
+  it('accepts a prefix option', () => {
+    expect(flatten({ play: 'Play' }, { prefix: 'buttons' })).toEqual({ 'buttons.play': 'Play' });
+  });
+});