How to separate variables in to arrays of 3?

Question

So What this is supposed to do, minus the mouseenter/mouseleave functions, is to take user input, divide it in to an array with 3 letters in each array placement (ex. User input abcdef... will turn in to abc, def,...). I read a different post on stack overflow, (How do you split a string at certain character numbers in javascript?). However, I can't quite get this to function in my following code.

Here is my script.js:

$(document).ready(function() {
    $('#button_translate').mouseenter(function() {
        $('#button_translate').fadeTo('fast', 1);
    });
    $('#button_translate').mouseleave(function() {
        $('#button_translate').fadeTo('fast', 0.7);
    });
    $('#button_clear').mouseenter(function() {
        $('#button_clear').fadeTo('fast', 1);
    });
    $('#button_clear').mouseleave(function() {
        $('#button_clear').fadeTo('fast', 0.7);
    });
    $('#button_translate').click(function() {
        var dna = $('input[name=dna]').val();
        var dna = dna.toUpperCase();
        function allBases(text) {  
            var bases = /^[ACGT]+$/;  
            if(text.match(bases)) {  

                var arr = Array.prototype.slice.call(dna), output = [];
                while (arr.length) output.push(arr.splice(0, 3).join('');
                document.write(arr + " is a DNA sequence.");

            }
            else
            {  
                document.write(dna + " is not a real DNA sequence.");
            }  
        }

        allBases(dna);

    });
});

Answer 1

I think this post might help:

Split string into array of equal length strings

Applying it to your code, you could replace:

    var arr = Array.prototype.slice.call(dna), output = [];
    while (arr.length) output.push(arr.splice(0, 3).join('');

with:

    var arr = text.match(/.{1,3}/g);

Answer 2

Just change this

while (arr.length) output.push(arr.splice(0, 3).join('');

to this

while (arr.length) output.push(arr.splice(0, 3).join(''));

Notice the difference ? Missing ) at the end !!.

Answer 3

You don't need looping, you could use a regular expression. If I assume you want to treat all characters equally (spaces, number, punctuation) then:

var userString = 'I am a terrible swimmer';
var resultArray = userString.match(/[\s\S]{1,3}/g);

\s\S = anything. {1,3} = between 1 and three charaters. This will give you groups of three characters, and whatever is left over at the end (for if your string has, say, four characters in it).