Question

I’m relatively new to javascript. I’m looking for a javascript function to get an arbitrary element of a given array based on a given string input.

A random(seed) function would be useful but I can’t find one.
Or maybe a way to xor hash the bytes in a string.

I can’t use jquery, and I’m hoping for an answer that’s relatively short.

Edit for examples:

var myArray = ["foo", "bar", "24", "asdf"];

the signature would look like

function ArbitraryElement(arr, seed)

and outputs would look something like:

ArbitraryElement(myArray, "what") // "foo"
ArbitraryElement(myArray, "that") // "24"
ArbitraryElement(myArray, "what") // "foo"
ArbitraryElement(myArray, "boo")  // "24"
ArbitraryElement(myArray, "cat")  // "asdf"
// etc...

Answer 1

You could sum the char codes with reduce, IE9 native and IE8 and below with shim included in link:

function ArbitraryElement(arr, seed) {
    seed = (seed || '') + "xx"; // ensure a seed that can be reduced
    var charCodes = seed.split('').reduce(function(a, b, i) {
        return (i == 1 ? a.charCodeAt(0) : +a) + b.charCodeAt(0);
    });
    return arr[charCodes % arr.length]
}

EDIT:

Here’s an update: http://jsfiddle.net/sqA6Z/