[2] Press "u" to update snapshots from watch mode

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

@@ -28,9 +28,11 @@ const check = (argv: Object) => {
     );
   }
 
-  if (argv.watchExtensions && argv.watch === undefined) {
+  if (argv.onlyChanged && argv.watchAll) {
     throw new Error(
-      '--watchExtensions can only be specified together with --watch.',
+      'Both --onlyChanged and --watchAll were specified, but these two ' +
+      'options do not make sense together. Try the --watch option which ' +
+      'reruns only tests related to changed files.',
     );
   }
 
@@ -148,10 +150,18 @@ const options = {
   watch: {
     description: wrap(
       'Watch files for changes and rerun tests related to changed files. ' +
-      'If you want to re-run all tests when a file has changed, you can ' +
-      'call Jest using `--watch=all`.',
+      'If you want to re-run all tests when a file has changed, use the ' +
+      '`--watchAll` option.',
     ),
-    type: 'string',
+    type: 'boolean',
+  },
+  watchAll: {
+    description: wrap(
+      'Watch files for changes and rerun all tests. If you want to re-run ' +
+       'only the tests related to the changed files, use the ' +
+      '`--watch` option.',
+    ),
+    type: 'boolean',
   },
   bail: {
     alias: 'b',

packages/jest-cli/src/jest.js

@@ -34,6 +34,12 @@ const CLEAR = '\x1B[2J\x1B[H';
 const VERSION = require('../package.json').version;
 const WATCHER_DEBOUNCE = 200;
 const WATCHMAN_BIN = 'watchman';
+const KEYS = {
+  CONTROL_C: '03',
+  CONTROL_D: '04',
+  ENTER: '0d',
+  U: '75',
+};
 
 function getMaxWorkers(argv) {
   if (argv.runInBand) {
@@ -51,7 +57,7 @@ function buildTestPathPatternInfo(argv) {
     return {
       lastCommit: argv.lastCommit,
       onlyChanged: true,
-      watch: argv.watch !== undefined,
+      watch: argv.watch,
     };
   }
   if (argv.testPathPattern) {
@@ -151,42 +157,74 @@ function runCLI(argv: Object, root: Path, onComplete: () => void) {
         pipe.write('test framework = ' + testFramework.name + '\n');
         pipe.write('config = ' + JSON.stringify(config, null, '  ') + '\n');
       }
-      if (argv.watch !== undefined) {
-        if (argv.watch !== 'all') {
-          argv.onlyChanged = true;
-        }
+      if (argv.watch || argv.watchAll) {
+        argv.onlyChanged = !argv.watchAll;
+
+        let isRunning: ?boolean;
+        let timer: ?number;
+
+        const startRun = (overrideConfig: Object = {}) => {
+          if (isRunning) {
+            return;
+          }
+
+          pipe.write(CLEAR);
+          isRunning = true;
+          runJest(
+            Object.freeze(Object.assign({}, config, overrideConfig)),
+            argv,
+            pipe,
+            () => {
+              isRunning = false;
+            },
+          ).then(
+            () => {},
+            error => console.error(chalk.red(error)),
+          );
+        };
+
+        const onKeypress = (key: string) => {
+          switch (key) {
+            case KEYS.CONTROL_C:
+              process.exit(0);
+              break;
+            case KEYS.CONTROL_D:
+              process.exit(0);
+              break;
+            case KEYS.ENTER:
+              startRun();
+              break;
+            case KEYS.U:
+              startRun({updateSnapshot: true});
+              break;
+          }
+        };
+
+        const onFileChange = (_, filePath: string) => {
+          filePath = path.join(root, filePath);
+          const isValidPath =
+            config.testPathDirs.some(dir => filePath.startsWith(dir));
 
-        return new Promise(resolve => {
-          getWatcher(config, root, watcher => {
-            let timer;
-            let isRunning;
-
-            pipe.write(CLEAR);
-            watcher.on('all', (_, filePath) => {
-              pipe.write(CLEAR);
-              filePath = path.join(root, filePath);
-              const isValidPath =
-                config.testPathDirs.some(dir => filePath.startsWith(dir));
-              if (!isRunning && isValidPath) {
-                if (timer) {
-                  clearTimeout(timer);
-                  timer = null;
-                }
-                timer = setTimeout(
-                  () => {
-                    isRunning = true;
-                    runJest(config, argv, pipe, () => isRunning = false)
-                      .then(
-                        resolve,
-                        error => console.error(chalk.red(error)),
-                      );
-                  },
-                  WATCHER_DEBOUNCE,
-                );
-              }
-            });
-          });
+          if (!isValidPath) {
+            return;
+          }
+          if (timer) {
+            clearTimeout(timer);
+            timer = null;
+          }
+          timer = setTimeout(startRun, WATCHER_DEBOUNCE);
+        };
+
+        if (typeof process.stdin.setRawMode === 'function') {
+          process.stdin.setRawMode(true);
+          process.stdin.resume();
+          process.stdin.setEncoding('hex');
+          process.stdin.on('data', onKeypress);
+        }
+        getWatcher(config, root, watcher => {
+          watcher.on('all', onFileChange);
         });
+        startRun();
       } else {
         return runJest(config, argv, pipe, onComplete);
       }

packages/jest-cli/src/reporters/SummaryReporter.js

@@ -62,7 +62,7 @@ class SummareReporter extends BaseReporter {
     }
 
     this._printSummary(aggregatedResults, config);
-    this._printSnapshotSummary(snapshots);
+    this._printSnapshotSummary(snapshots, config);
     if (totalTestSuites) {
       results +=
         `${PASS_COLOR(`${pluralize('test', passedTests)} passed`)} (` +
@@ -73,18 +73,23 @@ class SummareReporter extends BaseReporter {
     }
   }
 
-  _printSnapshotSummary(snapshots: SnapshotSummary) {
+  _printSnapshotSummary(snapshots: SnapshotSummary, config: Config) {
     if (
       snapshots.added ||
       snapshots.filesRemoved ||
       snapshots.unchecked ||
       snapshots.unmatched ||
       snapshots.updated
     ) {
+      let updateCommand;
       const event = process.env.npm_lifecycle_event;
-      const updateCommand =
-        (!event ? 're-' : '') + 'run with `' +
-        (event ? 'npm ' + event + ' -- ' : '') + '-u`';
+      if (config.watch) {
+        updateCommand = 'press "u"';
+      } else if (event) {
+        updateCommand = `run with \`npm ${event} -- -u\``;
+      } else {
+        updateCommand = 're-run with `-u`';
+      }
 
       this.log('\n' + SNAPSHOT_SUMMARY('Snapshot Summary'));
       if (snapshots.added) {

packages/jest-config/src/defaults.js

@@ -49,4 +49,5 @@ module.exports = ({
   testURL: 'about:blank',
   useStderr: false,
   verbose: false,
+  watch: false,
 }: DefaultConfig);

packages/jest-config/src/setFromArgv.js

@@ -64,6 +64,11 @@ function setFromArgv(config, argv) {
   if (argv.updateSnapshot) {
     config.updateSnapshot = argv.updateSnapshot;
   }
+
+  if (argv.watch || argv.watchAll) {
+    config.watch = true;
+  }
+
   config.noStackTrace = argv.noStackTrace;
 
   config.testcheckOptions = {

packages/jest-snapshot/src/SnapshotFile.js

@@ -63,6 +63,7 @@ class SnapshotFile {
     this._content = Object.create(null);
     if (this.fileExists(filename)) {
       try {
+        delete require.cache[require.resolve(filename)];
         /* eslint-disable no-useless-call */
         Object.assign(this._content, require.call(null, filename));
         /* eslint-enable no-useless-call */

types/Config.js

@@ -44,6 +44,7 @@ type BaseConfig = {
   testURL: string,
   useStderr: boolean,
   verbose: boolean,
+  watch: boolean,
 };
 
 export type DefaultConfig = BaseConfig & {