Reading value from console, interactively


I thought to make an simple server http server with some console extension. I found the snippet to read from command line data.

  var i = rl.createInterface(process.stdin, process.stdout, null);
  i.question('Write your name: ', function(answer) {
    console.log('Nice to meet you> ' + answer);


well to ask the questions repeatedly, i cant simply use the while(done) { } loop? Also well if the server receives output at the question time, it ruins the line.

12/20/2017 6:54:02 PM

Accepted Answer

you can't do a "while(done)" loop because that would require blocking on input, something node.js doesn't like to do.

Instead set up a callback to be called each time something is entered:

var stdin = process.openStdin();

stdin.addListener("data", function(d) {
    // note:  d is an object, and when converted to a string it will
    // end with a linefeed.  so we (rather crudely) account for that  
    // with toString() and then trim() 
    console.log("you entered: [" + 
        d.toString().trim() + "]");
1/29/2016 9:04:47 PM

I've used another API for this purpose..

var readline = require('readline');
var rl = readline.createInterface(process.stdin, process.stdout);
rl.setPrompt('guess> ');
rl.on('line', function(line) {
    if (line === "right") rl.close();

This allows to prompt in loop until the answer is right. Also it gives nice little console.You can find the details @

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