Sort Array Elements (string with numbers), natural sort

Question

I have an array like;

[\"IL0 Foo\", \"PI0 Bar\", \"IL10 Baz\", \"IL3 Bob says hello\"]

And need to sort it so it appears like;

Answer 1

I liked georg's solution a lot, but I needed underscores ("_") to sort before numbers. Here's how I modified his code:

var chunkRgx = /(_+)|([0-9]+)|([^0-9_]+)/g;
function naturalCompare(a, b) {
    var ax = [], bx = [];
    
    a.replace(chunkRgx, function(_, $1, $2, $3) {
        ax.push([$1 || "0", $2 || Infinity, $3 || ""])
    });
    b.replace(chunkRgx, function(_, $1, $2, $3) {
        bx.push([$1 || "0", $2 || Infinity, $3 || ""])
    });
    
    while(ax.length && bx.length) {
        var an = ax.shift();
        var bn = bx.shift();
        var nn = an[0].localeCompare(bn[0]) || 
                 (an[1] - bn[1]) || 
                 an[2].localeCompare(bn[2]);
        if(nn) return nn;
    }
    
    return ax.length - bx.length;
}

/////////////////////////

test = [
    "img12.png",
    "img10.png",
    "img2.png",
    "img1.png",
    "img101.png",
    "img101a.png",
    "abc10.jpg",
    "abc10",
    "abc2.jpg",
    "20.jpg",
    "20",
    "abc",
    "abc2",
    "_abc",
    "_ab_c",
    "_ab__c",
    "_abc_d",
    "ab_",
    "abc_",
    "_ab_cd",
    ""
];

test.sort(naturalCompare)
document.write("
" + JSON.stringify(test,0,3));