Rename plugin: pass back a list of modified files

packages/ts-migrate/cli.ts

@@ -84,8 +84,10 @@ yargs
     (args) => {
       const rootDir = path.resolve(process.cwd(), args.folder);
       const { sources } = args;
-      const exitCode = rename({ rootDir, sources });
-      process.exit(exitCode);
+      const renamedFiles = rename({ rootDir, sources });
+      if (renamedFiles === null) {
+        process.exit(-1);
+      }
     },
   )
   .command(

packages/ts-migrate/commands/rename.ts

@@ -11,24 +11,27 @@ interface RenameParams {
   sources?: string | string[];
 }
 
-export default function rename({ rootDir, sources }: RenameParams): number {
+export default function rename({
+  rootDir,
+  sources,
+}: RenameParams): Array<{ oldFile: string; newFile: string }> | null {
   const configFile = path.resolve(rootDir, 'tsconfig.json');
   if (!fs.existsSync(configFile)) {
     log.error('Could not find tsconfig.json at', configFile);
-    return -1;
+    return null;
   }
 
   let jsFiles: string[];
   try {
     jsFiles = findJSFiles(rootDir, configFile, sources);
   } catch (err) {
     log.error(err);
-    return -1;
+    return null;
   }
 
   if (jsFiles.length === 0) {
     log.info('No JS/JSX files to rename.');
-    return 0;
+    return [];
   }
 
   const toRename = jsFiles
@@ -55,7 +58,7 @@ export default function rename({ rootDir, sources }: RenameParams): number {
   updateProjectJson(rootDir);
 
   log.info('Done.');
-  return 0;
+  return toRename;
 }
 
 function findJSFiles(rootDir: string, configFile: string, sources?: string | string[]) {

packages/ts-migrate/tests/commands/rename/rename.test.ts

@@ -23,10 +23,36 @@ describe('rename command', () => {
     const outputDir = path.resolve(__dirname, 'output');
     copyDir(inputDir, rootDir);
 
-    const exitCode = rename({ rootDir });
+    const renamedFiles = rename({ rootDir });
+    const renamedFilesRelativeToRootDir = renamedFiles
+      ?.map(({ oldFile, newFile }) => {
+        const filePathRelativeToRootDir = (filePath: string) => path.relative(rootDir, filePath);
+        return {
+          oldFile: filePathRelativeToRootDir(oldFile),
+          newFile: filePathRelativeToRootDir(newFile),
+        };
+      })
+      .sort((a, b) => {
+        const getSortKey = ({ oldFile, newFile }: typeof a) => oldFile + newFile;
+        const sortKeyA = getSortKey(a);
+        const sortKeyB = getSortKey(b);
+
+        if (sortKeyA === sortKeyB) {
+          return 0;
+        }
+
+        return sortKeyA < sortKeyB ? -1 : 1;
+      });
 
     const [rootData, outputData] = getDirData(rootDir, outputDir);
     expect(rootData).toEqual(outputData);
-    expect(exitCode).toBe(0);
+    expect(renamedFilesRelativeToRootDir).toEqual([
+      { oldFile: 'dir-a/file-2.js', newFile: 'dir-a/file-2.ts' },
+      { oldFile: 'dir-a/file-3.jsx', newFile: 'dir-a/file-3.tsx' },
+      { oldFile: 'dir-a/file-4.js', newFile: 'dir-a/file-4.tsx' },
+      { oldFile: 'dir-a/file-5.js', newFile: 'dir-a/file-5.tsx' },
+      { oldFile: 'dir-a/file-6.js', newFile: 'dir-a/file-6.tsx' },
+      { oldFile: 'file-1.js', newFile: 'file-1.ts' },
+    ]);
   });
 });