Bun.js中循环外读取单行用户输入及进程终止问题

Bun.js有原生API支持循环读取用户输入，示例代码如下：

const prompt = "Type something: ";
process.stdout.write(prompt);
for await (const line of console) {
  console.log(`You typed: ${line}`);
  process.stdout.write(prompt);
}

但如果需要在循环外单次读取用户输入，可以通过process.stdin.iterator()实现：

const stdinIterator = process.stdin.iterator()

console.write('What is your first name?\n> ')
const firstName = (await stdinIterator.next()).value.toString().trimEnd()
console.log('Hello,', firstName)

console.write('What is your last name?\n> ')
const lastName = (await stdinIterator.next()).value.toString().trimEnd()
console.log('Welcome', `${firstName} ${lastName}`)

不过这段代码会导致进程无法自动终止，必须手动按下Ctrl+C结束。原因是stdin迭代器会保持事件循环处于活跃状态，阻止进程退出。

要解决这个问题，只需在读取完所有输入后，关闭stdin流或者直接终止进程：

方法1：关闭stdin流 #

const stdinIterator = process.stdin.iterator()

console.write('What is your first name?\n> ')
const firstName = (await stdinIterator.next()).value.toString().trimEnd()
console.log('Hello,', firstName)

console.write('What is your last name?\n> ')
const lastName = (await stdinIterator.next()).value.toString().trimEnd()
console.log('Welcome', `${firstName} ${lastName}`)

// 关闭stdin，允许进程自动终止
process.stdin.end()

方法2：直接终止进程 #

如果不需要等待其他异步任务执行，也可以直接调用process.exit()：

const stdinIterator = process.stdin.iterator()

console.write('What is your first name?\n> ')
const firstName = (await stdinIterator.next()).value.toString().trimEnd()
console.log('Hello,', firstName)

console.write('What is your last name?\n> ')
const lastName = (await stdinIterator.next()).value.toString().trimEnd()
console.log('Welcome', `${firstName} ${lastName}`)

// 直接终止进程
process.exit(0)

内容的提问来源于stack exchange，提问作者Mir-Ismaili