chore: convert walk to TS

packages/cli/src/commands/init/editTemplate.ts

@@ -1,7 +1,6 @@
 import fs from 'fs';
 import path from 'path';
 import {logger} from '@react-native-community/cli-tools';
-// @ts-ignore FIXME after converting walk to typescript
 import walk from '../../tools/walk';
 
 interface PlaceholderConfig {

packages/cli/src/tools/copyFiles.ts

@@ -7,7 +7,6 @@
 
 import fs from 'fs';
 import path from 'path';
-// @ts-ignore FIXME after converting walk to typescript
 import walk from './walk';
 
 type Options = {

packages/cli/src/tools/generator/copyProjectTemplateAndReplace.ts

@@ -11,7 +11,6 @@ import chalk from 'chalk';
 import path from 'path';
 import copyAndReplace from '../copyAndReplace';
 import promptInitializer from './promptSync';
-// @ts-ignore FIXME: walk should be ts
 import walk from '../walk';
 import {logger} from '@react-native-community/cli-tools';
 

packages/cli/src/tools/walk.js → packages/cli/src/tools/walk.ts

@@ -4,21 +4,21 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow
  */
 
 import fs from 'fs';
 import path from 'path';
 
-function walk(current: string) {
+function walk(current: string): string[] {
   if (!fs.lstatSync(current).isDirectory()) {
     return [current];
   }
 
   const files = fs
     .readdirSync(current)
     .map(child => walk(path.join(current, child)));
-  return [].concat.apply([current], files);
+  const result: string[] = [];
+  return result.concat.apply([current], files);
 }
 
 export default walk;