comb.js

comb.js

module.exports = function comb(matrix) {
    return Object.keys(matrix).reduce((res, k) => _fillIn(res, k, matrix[k]), [{}]);

    /**
     * Adds all combinations of existing array and incoming variants
     * @param {Array<Object>} combinations - existing combinations
     * @param {String} key - new key for items in combinations
     * @param {Array} values - values for new key
     * @returns {Array<Object>} - modified
     */
    function _fillIn(combinations, key, values) {
        var res = [];
        combinations.forEach(function(obj) {
            values.forEach(function(v) {
                var _new = _clone(obj);
                if (v !== undefined) _new[key] = v;
                res.push(_new);
            });
        });
        return res;
    }

    function _clone(old) {
        var _new = {};
        for (var k in old)
            if (old.hasOwnProperty(k))
                _new[k] = old[k];
        return _new;
    }
}

module.parent ||
    console.log(require('util').inspect(comb({
        kwas: ['1', '2', '3'],
        shelest: ['1', '2'],
        vobla: [undefined, 'defined']
    })));