关于脚手架:inquirer命令行交互原理二手写readline实现

背景

上篇曾经具体的形容了readline源码的实现，当初就是来测验下学习的状况，手动来实现一个readline

代码

(1)先监听输出流

function stepRead(callback) {  function onkeypress(s) {    output.write(s);  }  const input = process.stdin;  const output =  process.stdout;  let line = '';  emikeypressEvents(input);  input.on('keypress', onkeypress);};function emikeypressEvents(stream) {  function onData(chunk){    g.next(chunk.toString())  }  const g = emitkeys(stream);    g.next()    stream.on('data',onData)};function *emitkeys(stream) {  while(true){    let ch = yield;    stream.emit('keyPress',ch);  }}stepRead();

(2)一一字母监听输出流,并返回后果

知识点：
input.setRawMode(true);
input.resume(); // 从新开始，重启

function stepRead(callback) {  function onkeypress(s) {    output.write(s);    line += s;    switch (s) {      case '\r':        input.pause();        callback(line)        break;    }  }  const input = process.stdin;  const output =  process.stdout;  let line = '';  emitKeypressEvents(input);  input.on('keypress', onkeypress);  input.setRawMode(true);  input.resume();};function emitKeypressEvents(stream) {  function onData(chunk){    g.next(chunk.toString())  }  const g = emitkeys(stream);    g.next()    stream.on('data',onData)};function* emitkeys(stream) {  while(true){    let ch = yield;    stream.emit('keypress',ch);  }}stepRead(function(s){  console.log(s);  console.log('answer=', s);});

解说

（1）先将输出流和输入流进行缓存，将输出流要填写的信息放在line变量中；

const input = process.stdin; const output =  process.stdout; let line = '';

（2）调用emitKeypressEvents(input)，执行emitkyes的Generator函数。.next();stream.on('data',onData)绑定输出流

function emitKeypressEvents(stream) {  function onData(chunk){    g.next(chunk.toString())  }  const g = emitkeys(stream);    g.next()    stream.on('data',onData) };

function* emitkeys(stream) {  while(true){    let ch = yield;    stream.emit('keypress',ch);  }}

（3）input.on('keypress', onkeypress);绑定了onkeypress事件；输入流写入信息；如果是回车（'\r'）的话，shitch 来进行判断。

  function onkeypress(s) {    output.write(s); // 输出的信息进行打印    line += s;    switch (s) {      case '\r':        input.pause();        callback(line)        break;    }  }

目录

背景

代码

(1)先监听输出流

(2)一一字母监听输出流,并返回后果

解说