readline — 逐行读取

readline 模块用于从可读流中逐行读取数据。

import readline from 'readline'

创建 readline 接口

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
})

命令行交互

rl.question('你叫什么名字？ ', answer => {
  console.log(`你好, ${answer}!`)
  rl.close()
})

逐行读取文件

const rl = readline.createInterface({
  input: fs.createReadStream('file.txt'),
  crlfDelay: Infinity
})

rl.on('line', line => {
  console.log('行内容:', line)
})

rl.on('close', () => {
  console.log('文件读取完毕')
})

事件

事件	说明
line	读取到一行时触发
close	流关闭时触发
pause	输入流暂停时触发
resume	输入流恢复时触发
SIGINT	Ctrl+C 时触发

进阶：Promise 封装

function ask(question) {
  return new Promise(resolve => {
    const rl = readline.createInterface({
      input: process.stdin,
      output: process.stdout
    })
    rl.question(question, answer => {
      rl.close()
      resolve(answer)
    })
  })
}

const name = await ask('请输入名字: ')
console.log(`你好, ${name}`)