add clearCache cli command

integration_tests/__tests__/clear_cache.test.js

@@ -0,0 +1,37 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @flow
+ */
+'use strict';
+
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+const runJest = require('../runJest');
+
+const CACHE = path.resolve(os.tmpdir(), 'clear_cache_directory');
+
+describe('jest --clearCache', () => {
+  test('normal run results in cache directory being written', () => {
+    const {status} = runJest('clear_cache', [`--cacheDirectory=${CACHE}`]);
+
+    expect(fs.existsSync(CACHE)).toBe(true);
+    expect(status).toBe(0);
+  });
+  test('clearCache results in deleted directory and exit status 0', () => {
+    const {status, stdout, stderr} = runJest('clear_cache', [
+      '--clearCache',
+      `--cacheDirectory=${CACHE}`,
+    ]);
+
+    expect(fs.existsSync(CACHE)).toBe(false);
+    expect(stdout).toBe(`Cleared ${CACHE}\n`);
+    expect(stderr.trim()).toBe('');
+    expect(status).toBe(0);
+  });
+});

integration_tests/clear_cache/__tests__/clear_cache.test.js

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+'use strict';
+
+test('stub', () => expect(1).toBe(1));

integration_tests/clear_cache/package.json

@@ -0,0 +1,5 @@
+{
+  "jest": {
+    "testEnvironment": "node"
+  }
+}

packages/jest-cli/package.json

@@ -27,6 +27,7 @@
     "micromatch": "^2.3.11",
     "node-notifier": "^5.1.2",
     "pify": "^3.0.0",
+    "rimraf": "^2.5.4",
     "slash": "^1.0.0",
     "string-length": "^2.0.0",
     "strip-ansi": "^4.0.0",

packages/jest-cli/src/cli/args.js

@@ -117,6 +117,13 @@ export const options = {
       ' prevent snapshots from being written unless explicitly requested.',
     type: 'boolean',
   },
+  clearCache: {
+    default: undefined,
+    description:
+      'Clears the configured Jest cache directory and then exits. ' +
+      'Default directory can be found by calling jest --showConfig',
+    type: 'boolean',
+  },
   clearMocks: {
     default: undefined,
     description:

packages/jest-cli/src/cli/index.js

@@ -32,6 +32,7 @@ import Runtime from 'jest-runtime';
 import TestWatcher from '../test_watcher';
 import watch from '../watch';
 import yargs from 'yargs';
+import rimraf from 'rimraf';
 
 export async function run(maybeArgv?: Argv, project?: Path) {
   const argv: Argv = buildArgv(maybeArgv, project);
@@ -68,6 +69,15 @@ export const runCLI = async (
       outputStream,
     );
 
+    if (argv.clearCache) {
+      configs.forEach(config => {
+        rimraf.sync(config.cacheDirectory);
+        process.stdout.write(`Cleared ${config.cacheDirectory}\n`);
+      });
+
+      process.exit(0);
+    }
+
     await _run(
       globalConfig,
       configs,