node.js的readline模塊如何取兩次連續輸入？

Question

我正在創建一個程序來從命令行輸入兩個數字，然后在 node.js 中顯示總和。我正在使用 readline 模塊來獲取標准輸入。 下面是我的代碼。

const readline = require('readline');

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

const r2 = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});

rl.question('Please enter the first number', (answer1) => {
    r2.question('Please enter the second number', (answer2) => {
        var result = (+answer1) + (+answer2);
        console.log(`The sum of above two numbers is ${result}`);
    });
    rl.close();
});

這個程序只告訴我“請輸入第一個數字”，當我輸入像 5 這樣的數字時，第二個輸入也需要 5，並顯示答案 10

它根本不問第二個問題。 請檢查這個並告訴我問題是什么。 如果有任何更好的方法來獲取多個輸入，請告訴我。

我是node.js的新手用戶

Answer 1

不需要另一個變量，只需使用如下：

const readline = require('readline');

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

rl.question('Please enter the first number : ', (answer1) => {
    rl.question('Please enter the second number : ', (answer2) => {
        var result = (+answer1) + (+answer2);
        console.log(`The sum of above two numbers is ${result}`);
        rl.close();
    });
});

Answer 2

嵌套代碼/回調很難閱讀和維護，這是使用Promise提出多個問題的更優雅方式

節點8+

'use strict'

const readline = require('readline')

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

const question1 = () => {
  return new Promise((resolve, reject) => {
    rl.question('q1 What do you think of Node.js? ', (answer) => {
      console.log(`Thank you for your valuable feedback: ${answer}`)
      resolve()
    })
  })
}

const question2 = () => {
  return new Promise((resolve, reject) => {
    rl.question('q2 What do you think of Node.js? ', (answer) => {
      console.log(`Thank you for your valuable feedback: ${answer}`)
      resolve()
    })
  })
}

const main = async () => {
  await question1()
  await question2()
  rl.close()
}

main()

Answer 3

const readline = require("readline")

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

var questions = [
 "Input first number",
 "Input second number",
 "Input third number",
 "Input fourth number",
 "Input fifth number",
];

const askQuestion = (theQuestion) => {
    return new Promise((resolve, reject) => {
        try {
          rl.question(theQuestion + ": ", theAnswer => resolve(theAnswer));
        } catch {
          reject("No Answer");
        }
    })
}

async function start(){
    const answers = [];
    for (question of questions){
        answers.push(await askQuestion(question));
    }
    
    const total = answers.reduce((a, b) => {return Number(a) + Number(b)}); 
    console.log( `The sum of array ${answers} is ${total}`);
    rl.close();
}

start();
 

Answer 4

對於那些感興趣的人，我把這個小模塊放在一起，它接受一系列問題並返回一個解析為一系列答案的promise：

const readline = require('readline');

const AskQuestion = (rl, question) => {
    return new Promise(resolve => {
        rl.question(question, (answer) => {
            resolve(answer);
        });
    });
}

const Ask = function(questions) {
    return new Promise(async resolve => {
        let rl = readline.createInterface({
            input: process.stdin,
            output: process.stdout
        });

        let results = [];
        for(let i=0;i < questions.length;i++) {
            const result = await AskQuestion(rl, questions[i]);
            results.push(result);
        }
        rl.close();
        resolve(results);
    })
}

module.exports = {
    askQuestions: Ask 
}

將它保存在一個名為ask.js（或任何你喜歡的）的文件中並使用如下：

const { askQuestions } = require('./ask');

askQuestions([
   'What is question 1?',
   'What is question 2?',
   'What is question 3?'
])
    .then(answers => {
        // Do whatever you like with the array of answers
    });

注意：需要一個轉發器或最新版本的Node，因為它使用了很多ES6功能。

Answer 5

你可以使用遞歸：

var fs = require('fs')
var readline = require('readline')


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

 var keys = []
function gen(rank){
  if(rank > 3)
    {
        //do whatever u want
        var sum_avg = 0
        for (i in keys)
             {
                sum_avg+=Number(keys[i])
             }
         console.log(sum_avg/3); 
         return -1;     
    }
    else 
    { 
        var place = rank>1 ? "th" : "st"
        var total = rank+place 
        rl.question("Please enter the "+total+ " number :",function(answer){
            keys.push(answer)
            //this is where the recursion works
             gen(rank+1)
        })
     }
  }

//pass the value from where you want to start
  gen(1)

Answer 6

我會在異步函數中提出問題並將readline包裝成與Jason上面的方法類似。 雖然代碼略少:)

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

function question(theQuestion) {
    return new Promise(resolve => rl.question(theQuestion, answ => resolve(answ)))
}

async function askQuestions(){
    var answer = await question("A great question")
    console.log(answer);
}

Answer 7

const readline = require('readline');

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

const q0 = 'What\'s your name? Nicknames are also acceptable :)';
const q1 = 'What\'s an activity you like doing?';
const q2 = 'What do you listen to while doing that?';
const q3 = 'Which meal is your favourite (eg: dinner, brunch, etc.)';
const q4 = 'What\'s your favourite thing to eat for that meal?';
const q5 = 'Which sport is your absolute favourite?';
const q6 = 'What is your superpower? In a few words, tell us what you are amazing at!';

const arr = [q0, q1, q2, q3, q4, q5, q6];
let res = '';
const askQ = i => {
  if (i < arr.length) {
    rl.question(arr[i], (answer) => {
      res += '\n' + answer;
      askQ(i + 1);
    });
  } else {
      console.log(`Thank you for your valuable feedback: ${res}`);
      rl.close();
  }
};
askQ(0);

Answer 8

const readline = require('readline')

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

const question = (question) => {
  return new Promise((resolve, reject) => {
    rl.question(question, (answer) => {
      resolve(answer)
    })
  })
}

const main = async () => {
  const username = await question('Please enter a username: ');
  const password = await question('Please enter a password: ');
  console.log("result: ", {
      "username" : username,
      "password" : password
  });
  rl.close()
}

main()

我決定簡化 @jc 為希望從問題中獲得輸出的開發人員編寫的代碼。

Answer 9

為了獲得更多優化代碼，我找到了一個 package node-quick-cli

它不支持 require() 以支持將文件名.js 更改為.mjs

import readline from 'node-quick-cli';
var readlineq = new readline();
(async () => {
    console.log(await readlineq.question('Question 1 : '));
    console.log(await readlineq.question('question 3 : ',{color:"blue"}));
    console.log(await readlineq.question('Question 2 : ',{bgcolor:"bgBlue"}));
    readlineq.close();
})();

Answer 10

import readline from 'readline'

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

multiLineCI()

async function multiLineCI() {

     const credentials = {
         server: await new Promise( rsl => CLI.question( 'enter server: ' , ans => rsl( ans ) ) ),
         port: await new Promise( rsl => CLI.question( 'enter port: ' , ans => rsl( ans ) ) ),
         username: await new Promise( rsl => CLI.question( 'enter username: ' , ans => rsl( ans ) ) ),
         password: await new Promise( rsl => CLI.question( 'enter password: ' , ans => rsl( ans ) ) )
     }
     
     console.log( credentials )
     
     CLI.close()

}