Javascript实现笛卡儿积算法

在根据商品属性计算SKU时，通常会对商品不同选项的不同属性进行笛卡儿积运算。

function cartesian(elements) {
    if (!Array.isArray(elements))
        throw new TypeError();
    var end = elements.length - 1,
        result = [];

    function addTo(curr, start) {
        var first = elements[start],
            last = (start === end);
        for (var i = 0; i < first.length; ++i) {
            var copy = curr.slice();
            copy.push(first[i]);
            if (last) {
                result.push(copy);
            } else {
                addTo(copy, start + 1);
            }
        }
    }

    if (elements.length)
        addTo([], 0);
    else
        result.push([]);
    return result;
}

const result = cartesian([[1, 2], ['a', 'b'], [true, false]]);
console.log(result);