Add support for non-interactive terminal

packages/react-scripts/scripts/start.js

@@ -35,6 +35,7 @@ var paths = require('../config/paths');
 
 var useYarn = pathExists.sync(paths.yarnLockFile);
 var cli = useYarn ? 'yarn' : 'npm';
+var isInteractive = process.stdout.isTTY;
 
 // Warn and crash if required files are missing
 if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
@@ -69,21 +70,33 @@ function setupCompiler(host, port, protocol) {
  // bundle, so if you refresh, it'll wait instead of serving the old one.
  // "invalid" is short for "bundle invalidated", it doesn't imply any errors.
  compiler.plugin('invalid', function() {
- clearConsole();
+ if (isInteractive) {
+ clearConsole();
+ }
  console.log('Compiling...');
  });
 
+ var isFirstCompile = true;
+
  // "done" event fires when Webpack has finished recompiling the bundle.
  // Whether or not you have warnings or errors, you will get this event.
  compiler.plugin('done', function(stats) {
- clearConsole();
+ if (isInteractive) {
+ clearConsole();
+ }
 
  // We have switched off the default Webpack output in WebpackDevServer
  // options so we are going to "massage" the warnings and errors and present
  // them in a readable focused way.
  var messages = formatWebpackMessages(stats.toJson({}, true));
- if (!messages.errors.length && !messages.warnings.length) {
+ var isSuccessful = !messages.errors.length && !messages.warnings.length;
+ var showInstructions = isSuccessful && (isInteractive || isFirstCompile);
+
+ if (isSuccessful) {
  console.log(chalk.green('Compiled successfully!'));
+ }
+
+ if (showInstructions) {
  console.log();
  console.log('The app is running at:');
  console.log();
@@ -92,6 +105,7 @@ function setupCompiler(host, port, protocol) {
  console.log('Note that the development build is not optimized.');
  console.log('To create a production build, use ' + chalk.cyan(cli + ' run build') + '.');
  console.log();
+ isFirstCompile = false;
  }
 
  // If errors exist, only show errors.
@@ -258,10 +272,15 @@ function runDevServer(host, port, protocol) {
  return console.log(err);
  }
 
- clearConsole();
+ if (isInteractive) {
+ clearConsole();
+ }
  console.log(chalk.cyan('Starting the development server...'));
  console.log();
- openBrowser(protocol + ':https://' + host + ':' + port + '/');
+
+ if (isInteractive) {
+ openBrowser(protocol + ':https://' + host + ':' + port + '/');
+ }
  });
 }
 
@@ -280,16 +299,20 @@ detect(DEFAULT_PORT).then(port => {
  return;
  }
 
- clearConsole();
- var existingProcess = getProcessForPort(DEFAULT_PORT);
- var question =
- chalk.yellow('Something is already running on port ' + DEFAULT_PORT + '.' +
- ((existingProcess) ? ' Probably:\n ' + existingProcess : '')) +
- '\n\nWould you like to run the app on another port instead?';
+ if (isInteractive) {
+ clearConsole();
+ var existingProcess = getProcessForPort(DEFAULT_PORT);
+ var question =
+ chalk.yellow('Something is already running on port ' + DEFAULT_PORT + '.' +
+ ((existingProcess) ? ' Probably:\n ' + existingProcess : '')) +
+ '\n\nWould you like to run the app on another port instead?';
 
- prompt(question, true).then(shouldChangePort => {
- if (shouldChangePort) {
- run(port);
- }
- });
+ prompt(question, true).then(shouldChangePort => {
+ if (shouldChangePort) {
+ run(port);
+ }
+ });
+ } else {
+ console.log(chalk.red('Something is already running on port ' + DEFAULT_PORT + '.'));
+ }
 });