Node.js prompt skipping input

Question

I'm currently taking a course on Coursera, and doing an exercise using node.js code to calculate a quadratic expression. All the code is given and this exercise is merely to get us to know node.js, but still I'm encountering a problem entering a prompt.
the code is here:

var quad = require('./quadratic');

var prompt = require('prompt');

prompt.get(['a', 'b', 'c'], function (err, result) {
    if (err) { return onErr(err); }
    console.log('Command-line input received:');
    console.log('a: ' + result.a);
    console.log('b: ' + result.b);
    console.log('c: ' + result.c);

        quad(result.a,result.b,result.c, function(err,quadsolve) {
            if (err) {
                 console.log('Error: ', err);
                }
                else {
             console.log("Roots are "+quadsolve.root1() + "  " + quadsolve.root2());
                }
       });
});

As you see, I'm using the prompt module, but when I enter the input for a, the cmd is skipping the input for b and requesting me to enter `c, which in turn of couse, resulting in an error.

How to fix this issue, and why does it happen?

what are your key strokes when entering the values? Perhaps something is counted as an input or "return" that you are not expecting. — clay
– clay, Commented Nov 15, 2015 at 1:04
@clay simply the number and then I press enter. I also tried just to press enter, the result is the same. — Gershon Papi
– Gershon Papi, Commented Nov 15, 2015 at 3:26
Are you on Windows? You might be running into this issue: github.com/flatiron/prompt/issues/131 — clay
– clay, Commented Nov 15, 2015 at 19:33

Leah Zorychta · Accepted Answer · 2015-11-15 22:36:07Z

3

Welcome to developing on windows! Windows uses a carriage return in addition to a \n line ending which is probably why you see this bug. You can force prompt to tokenize on a regular expression like this, which should hopefully fix your issue:

  var schema = {
    properties: {
      a: { pattern: /^[0-9]+$/, message: 'a', required: true },
      b: { pattern: /^[0-9]+$/, message: 'b', required: true },
      c: { pattern: /^[0-9]+$/, message: 'c', required: true }
    }
  };

  prompt.get(schema, function (err, result) {
      // .. rest of your code
  });

answered Nov 15, 2015 at 22:36

Leah Zorychta

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