open 開啟瀏覽器的過程原理範例解析

module.exports = {
  //...
  devServer: {
    open: true,
  },
};

# yarn serve 不會自動開啟瀏覽器 
yarn serve 
# --open 引數後會自動開啟瀏覽器 
yarn serve --open

const open = (target, options) => {
	if (typeof target !== 'string') {
		throw new TypeError('Expected a `target`');
	}
	return baseOpen({
		...options,
		target
	});
};

const path = require('path');
const childProcess = require('child_process');
const {promises: fs, constants: fsConstants} = require('fs');
const {platform, arch} = process;
const baseOpen = async options => {
	options = {
		wait: false,
		background: false,
		newInstance: false,
		allowNonzeroExitCode: false,
		...options
	};
	// ... 部分程式碼...
	let command;
	const cliArguments = [];
	const childProcessOptions = {};
	if (platform === 'darwin') {
		command = 'open';
		if (options.wait) {
			cliArguments.push('--wait-apps');
		}
                // ...省略一些判斷，
	} else if (platform === 'win32' || (isWsl && !isDocker())) {
		const mountPoint = await getWslDrivesMountPoint();
		command = isWsl ?
			`${mountPoint}c/Windows/System32/WindowsPowerShell/v1.0/powershell.exe` :
			`${process.env.SYSTEMROOT}\System32\WindowsPowerShell\v1.0\powershell`;
		cliArguments.push(
			'-NoProfile',
			'-NonInteractive',
			'–ExecutionPolicy',
			'Bypass',
			'-EncodedCommand'
		);
		if (app) {
			// Double quote with double quotes to ensure the inner quotes are passed through.
			// Inner quotes are delimited for PowerShell interpretation with backticks.
			encodedArguments.push(`"`"${app}`""`, '-ArgumentList');
			if (options.target) {
				appArguments.unshift(options.target);
			}
		} else if (options.target) {
			encodedArguments.push(`"${options.target}"`);
		}
		if (appArguments.length > 0) {
			appArguments = appArguments.map(arg => `"`"${arg}`""`);
			encodedArguments.push(appArguments.join(','));
		}
		// Using Base64-encoded command, accepted by PowerShell, to allow special characters.
		options.target = Buffer.from(encodedArguments.join(' '), 'utf16le').toString('base64');
	} else {
           // ...省略 其他情況
	}
	if (options.target) {
		cliArguments.push(options.target);
	}
	if (platform === 'darwin' && appArguments.length > 0) {
		cliArguments.push('--args', ...appArguments);
	}
	const subprocess = childProcess.spawn(command, cliArguments, childProcessOptions);
	if (options.wait) {
		return new Promise((resolve, reject) => {
			subprocess.once('error', reject);
			subprocess.once('close', exitCode => {
				if (options.allowNonzeroExitCode && exitCode > 0) {
					reject(new Error(`Exited with code ${exitCode}`));
					return;
				}
				resolve(subprocess);
			});
		});
	}
	subprocess.unref();
	return subprocess;
};