Using recursion to make an array of all product options

product-options-with-recursion.js

var options = [
  ["red", "blue", "green", "yellow"], // color
  ["small", "medium", "large"],       // size
  ["heavy", "light"],                 // thickness
];
scope.inventory = findPermutations(options);

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

function findPermutations(options) {
    var resp = [];
    if (options.length){
      recur(options); // kick off the recursion
    }
    return resp;

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

    function recur(choices, aggr) {
        var aggr = aggr || []; // aggregator

        // We hit the bottom of our recursion
        if (!choices.length) {
            // write out to outer variable
            resp.push(aggr);
            return aggr;
        }

        // always loop over the first item we are given
        for (var c = 0; c < choices[0].length; c++) {
            // remove the first option and pass it back in
            // pass the remaining choices
            recur(choices.slice(1), aggr.concat(choices[0][c]));
        }
    }
}