feat: add option for JSON output (#179)

* Add option for JSON output file

* Moved back to JSON output

Author: AlexanderKaran

src/cli.ts

@@ -29,9 +29,13 @@ const subCommands = new Map<string, LazyCommand<any>>([
   ['migrate', lazy(migrateCommand, migrateMeta)]
 ]);
 
-cli(process.argv.slice(2), defaultCommand, {
+const args = process.argv.slice(2);
+const isJsonMode = args[0] === 'analyze' && args.includes('--json');
+
+cli(args, defaultCommand, {
   name: 'cli',
   version,
   description: `${styleText('cyan', 'e18e')}`,
-  subCommands
+  subCommands,
+  renderHeader: isJsonMode ? null : undefined
 });

src/commands/analyze.meta.ts

@@ -14,6 +14,11 @@ export const meta = {
       multiple: true,
       description:
         'Path(s) to custom manifest file(s) for module replacements analysis'
+    },
+    json: {
+      type: 'boolean',
+      default: false,
+      description: 'Output results as JSON to stdout'
     }
   }
 } as const;

src/commands/analyze.ts

@@ -37,14 +37,17 @@ export async function run(ctx: CommandContext<typeof meta>) {
   const providedPath =
     ctx.positionals.length > 1 ? ctx.positionals[1] : undefined;
   const logLevel = ctx.values['log-level'];
-  let root: string | undefined = undefined;
+  const jsonOutput = ctx.values['json'];
+  let root: string | undefined;
 
   // Enable debug output based on log level
   if (logLevel === 'debug') {
     enableDebug('e18e:*');
   }
 
-  prompts.intro('Analyzing...');
+  if (!jsonOutput) {
+    prompts.intro('Analyzing...');
+  }
 
   // Path can be a directory (analyze project)
   if (providedPath) {
@@ -56,7 +59,11 @@ export async function run(ctx: CommandContext<typeof meta>) {
     }
 
     if (!stat || !stat.isDirectory()) {
-      prompts.cancel(`Path must be a directory: ${providedPath}`);
+      if (jsonOutput) {
+        process.stderr.write(`Path must be a directory: ${providedPath}\n`);
+      } else {
+        prompts.cancel(`Path must be a directory: ${providedPath}`);
+      }
       process.exit(1);
     }
 
@@ -71,6 +78,19 @@ export async function run(ctx: CommandContext<typeof meta>) {
     manifest: customManifests
   });
 
+  const thresholdRank = FAIL_THRESHOLD_RANK[logLevel] ?? 0;
+  const hasFailingMessages =
+    thresholdRank > 0 &&
+    messages.some((m) => SEVERITY_RANK[m.severity] >= thresholdRank);
+
+  if (jsonOutput) {
+    process.stdout.write(JSON.stringify({stats, messages}, null, 2) + '\n');
+    if (hasFailingMessages) {
+      process.exit(1);
+    }
+    return;
+  }
+
   prompts.log.info('Summary');
 
   const totalDeps =
@@ -197,10 +217,6 @@ export async function run(ctx: CommandContext<typeof meta>) {
   prompts.outro('Done!');
 
   // Exit with non-zero when messages meet the fail threshold (--log-level)
-  const thresholdRank = FAIL_THRESHOLD_RANK[logLevel] ?? 0;
-  const hasFailingMessages =
-    thresholdRank > 0 &&
-    messages.some((m) => SEVERITY_RANK[m.severity] >= thresholdRank);
   if (hasFailingMessages) {
     process.exit(1);
   }

src/test/cli.test.ts

@@ -157,6 +157,40 @@ describe('analyze exit codes', () => {
   });
 });
 
+describe('analyze --json', () => {
+  beforeAll(async () => {
+    const nodeModules = path.join(basicChalkFixture, 'node_modules');
+    if (!existsSync(nodeModules)) {
+      execSync('npm install', {cwd: basicChalkFixture, stdio: 'pipe'});
+    }
+  });
+
+  it('outputs valid JSON to stdout', async () => {
+    const {stdout, code} = await runCliProcess(
+      ['analyze', '--json', '--log-level=error'],
+      tempDir
+    );
+    expect(code).toBe(0);
+    const parsed = JSON.parse(stdout);
+    expect(parsed).toHaveProperty('stats');
+    expect(parsed).toHaveProperty('messages');
+    expect(parsed.stats).toHaveProperty('name', 'mock-package');
+    expect(parsed.stats).toHaveProperty('version', '1.0.0');
+    expect(parsed.stats).toHaveProperty('dependencyCount');
+    expect(Array.isArray(parsed.messages)).toBe(true);
+  });
+
+  it('exits 1 with --json when messages meet fail threshold', async () => {
+    const {stdout, code} = await runCliProcess(
+      ['analyze', '--json'],
+      basicChalkFixture
+    );
+    expect(code).toBe(1);
+    const parsed = JSON.parse(stdout);
+    expect(parsed.messages.length).toBeGreaterThan(0);
+  });
+});
+
 describe('analyze fixable summary', () => {
   it('includes fixable-by-migrate summary when project has fixable replacement', async () => {
     const {stdout, stderr, code} = await runCliProcess(