Fixes facebook#9294

Differential Revision: D3752878

fbshipit-source-id: f248082effde9133dd6a9edf8a2f2cfc05279eab

Author: grabbou

local-cli/link/__tests__/android/makeStringsPatch.spec.js

@@ -0,0 +1,20 @@
+'use strict';
+
+jest.autoMockOff();
+
+const makeStringsPatch = require('../../android/patches/makeStringsPatch');
+
+describe('makeStringsPatch', () => {
+  it('should export a patch with <string> element', () => {
+    const params = {
+      keyA: 'valueA',
+    };
+
+    expect(makeStringsPatch(params, 'module').patch)
+      .toContain('<string moduleConfig="true" name="module_keyA">valueA</string>');
+  });
+
+  it('should export an empty patch if no params given', () => {
+    expect(makeStringsPatch({}, 'module').patch).toBe('');
+  });
+});

local-cli/link/android/patches/makeStringsPatch.js

@@ -1,14 +1,19 @@
 const toCamelCase = require('lodash').camelCase;
 
 module.exports = function makeStringsPatch(params, prefix) {
-  const patch = Object.keys(params).map(param => {
-    const name = toCamelCase(prefix) + '_' + param;
-    return '    ' +
-      `<string moduleConfig="true" name="${name}">${params[param]}</string>`;
-  }).join('\n') + '\n';
+  const values = Object.keys(params)
+    .map(param => {
+      const name = toCamelCase(prefix) + '_' + param;
+      return '    ' +
+        `<string moduleConfig="true" name="${name}">${params[param]}</string>`;
+    });
+
+  const patch = values.length > 0
+    ? values.join('\n') + '\n'
+    : '';
 
   return {
     pattern: '<resources>\n',
-    patch: patch,
+    patch,
   };
 };