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create-react-app/scripts/start.js
2016-09-02 20:27:58 +01:00

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JavaScript
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// @remove-on-eject-begin
/**
* Copyright (c) 2015-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.
*/
// @remove-on-eject-end
process.env.NODE_ENV = 'development';
var path = require('path');
var chalk = require('chalk');
var webpack = require('webpack');
var WebpackDevServer = require('webpack-dev-server');
var historyApiFallback = require('connect-history-api-fallback');
var httpProxyMiddleware = require('http-proxy-middleware');
var execSync = require('child_process').execSync;
var opn = require('opn');
var detect = require('detect-port');
var prompt = require('./utils/prompt');
var config = require('../config/webpack.config.dev');
var paths = require('../config/paths');
// Tools like Cloud9 rely on this.
var DEFAULT_PORT = process.env.PORT || 3000;
var compiler;
var handleCompile;
// You can safely remove this after ejecting.
// We only use this block for testing of Create React App itself:
var isSmokeTest = process.argv.some(arg => arg.indexOf('--smoke-test') > -1);
if (isSmokeTest) {
handleCompile = function (err, stats) {
if (err || stats.hasErrors() || stats.hasWarnings()) {
process.exit(1);
} else {
process.exit(0);
}
};
}
// Some custom utilities to prettify Webpack output.
// This is a little hacky.
// It would be easier if webpack provided a rich error object.
var friendlySyntaxErrorLabel = 'Syntax error:';
function isLikelyASyntaxError(message) {
return message.indexOf(friendlySyntaxErrorLabel) !== -1;
}
function formatMessage(message) {
return message
// Make some common errors shorter:
.replace(
// Babel syntax error
'Module build failed: SyntaxError:',
friendlySyntaxErrorLabel
)
.replace(
// Webpack file not found error
/Module not found: Error: Cannot resolve 'file' or 'directory'/,
'Module not found:'
)
// Internal stacks are generally useless so we strip them
.replace(/^\s*at\s.*:\d+:\d+[\s\)]*\n/gm, '') // at ... ...:x:y
// Webpack loader names obscure CSS filenames
.replace('./~/css-loader!./~/postcss-loader!', '');
}
function clearConsole() {
// This seems to work best on Windows and other systems.
// The intention is to clear the output so you can focus on most recent build.
process.stdout.write('\x1bc');
}
function setupCompiler(port) {
// "Compiler" is a low-level interface to Webpack.
// It lets us listen to some events and provide our own custom messages.
compiler = webpack(config, handleCompile);
// "invalid" event fires when you have changed a file, and Webpack is
// recompiling a bundle. WebpackDevServer takes care to pause serving the
// 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();
console.log('Compiling...');
});
// "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();
var hasErrors = stats.hasErrors();
var hasWarnings = stats.hasWarnings();
if (!hasErrors && !hasWarnings) {
console.log(chalk.green('Compiled successfully!'));
console.log();
console.log('The app is running at:');
console.log();
console.log(' ' + chalk.cyan('http://localhost:' + port + '/'));
console.log();
console.log('Note that the development build is not optimized.');
console.log('To create a production build, use ' + chalk.cyan('npm run build') + '.');
console.log();
return;
}
// 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.
// We use stats.toJson({}, true) to make output more compact and readable:
// https://github.com/facebookincubator/create-react-app/issues/401#issuecomment-238291901
var json = stats.toJson({}, true);
var formattedErrors = json.errors.map(message =>
'Error in ' + formatMessage(message)
);
var formattedWarnings = json.warnings.map(message =>
'Warning in ' + formatMessage(message)
);
if (hasErrors) {
console.log(chalk.red('Failed to compile.'));
console.log();
if (formattedErrors.some(isLikelyASyntaxError)) {
// If there are any syntax errors, show just them.
// This prevents a confusing ESLint parsing error
// preceding a much more useful Babel syntax error.
formattedErrors = formattedErrors.filter(isLikelyASyntaxError);
}
formattedErrors.forEach(message => {
console.log(message);
console.log();
});
// If errors exist, ignore warnings.
return;
}
if (hasWarnings) {
console.log(chalk.yellow('Compiled with warnings.'));
console.log();
formattedWarnings.forEach(message => {
console.log(message);
console.log();
});
// Teach some ESLint tricks.
console.log('You may use special comments to disable some warnings.');
console.log('Use ' + chalk.yellow('// eslint-disable-next-line') + ' to ignore the next line.');
console.log('Use ' + chalk.yellow('/* eslint-disable */') + ' to ignore all warnings in a file.');
}
});
}
function openBrowser(port) {
if (process.platform === 'darwin') {
try {
// Try our best to reuse existing tab
// on OS X Google Chrome with AppleScript
execSync('ps cax | grep "Google Chrome"');
execSync(
'osascript chrome.applescript http://localhost:' + port + '/',
{cwd: path.join(__dirname, 'utils'), stdio: 'ignore'}
);
return;
} catch (err) {
// Ignore errors.
}
}
// Fallback to opn
// (It will always open new tab)
opn('http://localhost:' + port + '/');
}
function addMiddleware(devServer) {
// `proxy` lets you to specify a fallback server during development.
// Every unrecognized request will be forwarded to it.
var proxy = require(paths.appPackageJson).proxy;
devServer.use(historyApiFallback({
// Allow paths with dots in them to be loaded, reference issue #387
disableDotRule: true,
// For single page apps, we generally want to fallback to /index.html.
// However we also want to respect `proxy` for API calls.
// So if `proxy` is specified, we need to decide which fallback to use.
// We use a heuristic: if request `accept`s text/html, we pick /index.html.
// Modern browsers include text/html into `accept` header when navigating.
// However API calls like `fetch()` wont generally wont accept text/html.
// If this heuristic doesnt work well for you, dont use `proxy`.
htmlAcceptHeaders: proxy ?
['text/html'] :
['text/html', '*/*']
}));
if (proxy) {
if (typeof proxy !== 'string') {
console.log(chalk.red('When specified, "proxy" in package.json must be a string.'));
console.log(chalk.red('Instead, the type of "proxy" was "' + typeof proxy + '".'));
console.log(chalk.red('Either remove "proxy" from package.json, or make it a string.'));
process.exit(1);
}
// Otherwise, if proxy is specified, we will let it handle any request.
// There are a few exceptions which we won't send to the proxy:
// - /index.html (served as HTML5 history API fallback)
// - /*.hot-update.json (WebpackDevServer uses this too for hot reloading)
// - /sockjs-node/* (WebpackDevServer uses this for hot reloading)
// Tip: use https://www.debuggex.com/ to visualize the regex
var mayProxy = /^(?!\/(index\.html$|.*\.hot-update\.json$|sockjs-node\/)).*$/;
devServer.use(mayProxy,
// Pass the scope regex both to Express and to the middleware for proxying
// of both HTTP and WebSockets to work without false positives.
httpProxyMiddleware(pathname => mayProxy.test(pathname), {
target: proxy,
logLevel: 'silent',
secure: false,
changeOrigin: true
})
);
}
// Finally, by now we have certainly resolved the URL.
// It may be /index.html, so let the dev server try serving it again.
devServer.use(devServer.middleware);
}
function runDevServer(port) {
var devServer = new WebpackDevServer(compiler, {
// Enable hot reloading server. It will provide /sockjs-node/ endpoint
// for the WebpackDevServer client so it can learn when the files were
// updated. The WebpackDevServer client is included as an entry point
// in the Webpack development configuration. Note that only changes
// to CSS are currently hot reloaded. JS changes will refresh the browser.
hot: true,
// It is important to tell WebpackDevServer to use the same "root" path
// as we specified in the config. In development, we always serve from /.
publicPath: config.output.publicPath,
// WebpackDevServer is noisy by default so we emit custom message instead
// by listening to the compiler events with `compiler.plugin` calls above.
quiet: true,
// Reportedly, this avoids CPU overload on some systems.
// https://github.com/facebookincubator/create-react-app/issues/293
watchOptions: {
ignored: /node_modules/
}
});
// Our custom middleware proxies requests to /index.html or a remote API.
addMiddleware(devServer);
// Launch WebpackDevServer.
devServer.listen(port, (err, result) => {
if (err) {
return console.log(err);
}
clearConsole();
console.log(chalk.cyan('Starting the development server...'));
console.log();
openBrowser(port);
});
}
function run(port) {
setupCompiler(port);
runDevServer(port);
}
// We attempt to use the default port but if it is busy, we offer the user to
// run on a different port. `detect()` Promise resolves to the next free port.
detect(DEFAULT_PORT).then(port => {
if (port === DEFAULT_PORT) {
run(port);
return;
}
clearConsole();
var question =
chalk.yellow('Something is already running on port ' + DEFAULT_PORT + '.') +
'\n\nWould you like to run the app on another port instead?';
prompt(question, true).then(shouldChangePort => {
if (shouldChangePort) {
run(port);
}
});
});