String concatenation in javascript outputs bad result

Question

I want to create random usernames. I use a list names and firstnames from a file and get one from each files randomly.

var nameList= fs.readFileSync("random-name/names.txt").toString().split("\n");
var name = nameList[Math.ceil(Math.random()*nameList.length)];

var firstnameList= fs.readFileSync("random-name/first-names.txt").toString().split("\n");
var firstname= firstnameList[Math.ceil(Math.random()*firstnameList.length)];

The problem appears when I want to concatenate them:

console.log( name);
console.log( firstname);
console.log( firstname+"-"+name);

outputs:

Brant
Jesselyn
-Brantyn

There is obviously no problem if I set the variable name and firstname statically.

Maybe there is a CR character at the end of firstname? Try to print the string lengths... — Emanuele Paolini
– Emanuele Paolini, Commented Nov 15, 2015 at 12:42

Gaël Barbin · Accepted Answer · 2015-11-15 12:43:22Z

2

The problem occurs because I splitted the file content with "\n", and there was still "\r" at the end of each names and firstnames.

answered Nov 15, 2015 at 12:43

Gaël Barbin

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Comments

Tomalak · Accepted Answer · 2015-11-15 12:51:18Z

1

As you've noted yourself, remove \r from the input, or alternatively split on \r?\n.

Other notes:

Don't repeat yourself.
Your "random item" calculation is wrong, you should be using floor, not ceil.

How about:

function getLines(filename) {
    return fs.readFileSync(filename).toString().split(/\r?\n/);
}
Array.prototype.getRandomItem = function () {
    return this[Math.floor(Math.random() * this.length)];
};

and

var nameList = getLines("random-name/names.txt");
var name = nameList.getRandomItem();

var firstnameList = getLines("random-name/first-names.txt");
var firstname = firstnameList.getRandomItem();

answered Nov 15, 2015 at 12:51

Tomalak

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