Generate all combinations JavaScript

[betazold]

var a = [
    ['a', 'b', 'c'],
    ['e', 'f'],
    ['g', 'h', 'i', 'j'],
    ['k']
];
 
var f = function (data, i) {
    var result = [],
        tmp,
        j, k,
        variants;
    // start from 0 index of data at function launch if index wasn't passed
    i = i || 0;
    // in case i is greater then array bound, just return empty array
    if (i < data.length) {
        for (j = 0; j < data[i].length; j++) {
            variants = f(data, i + 1);
            // if there aren't variants, just create array of one element which is empty array itself
            if (!variants.length) {
                variants = [
                    []
                ];
            }
            for (k = 0; k < variants.length; k++) {
                // concat variants and current iterable element
                tmp = [data[i][j]].concat(variants[k]);
                result.push(tmp);
            }
        }
    }
    return result;
}
 
console.log(f(a));

@темы: JavaScript, algorithms, combinatoric