Getting user's input in NodeJS "readline" module

Question

In a NodeJS program, I want to accept input from console. I chose readline to do this. The code can be simplified as follow:

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

function getInput() {
    rl.question("", (ans) => {
        console.log(ans);
    })
}

getInput();
rl.close();

But every time I run this program, it exits before I could make any input.

I think the problem is caused by the statement rl.close(), it may close the interface before accepting any input. How can I avoid this?

Thanks for answering!

lastr2d2 · Accepted Answer · 2021-02-01 02:23:31Z

2

Wrap the getInput in a promise like this:

function getInput() {
    return new Promise(function (resolve, reject) {
        rl.question("what's your option? ", (ans) => {
            console.log(ans);
            resolve(ans);
        });
    });
}

// and await here

await getInput();
rl.close();

answered Feb 1, 2021 at 2:23

lastr2d2

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3 Comments

atzlt Over a year ago

No, it doesn't work. It sais await can only be used in async functions: await getInput(); ^^^^^ SyntaxError: await is only valid in async function

lastr2d2 Over a year ago

that's a different question but you can wrap it in an async method like this. (async()=>{ await getInput(); rl.close(); })();

lastr2d2 Over a year ago

Or the old call back way getInput().then(()=>{rl.close();}) if you are not comfortable with the await sytax.

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