数组转树结构

function toTree(arr, parentcode) {
    const tree = [];
    arr.forEach(p => {
        const codeArr = p.code.split('-');
        const curNodeParentcode = codeArr.splice(codeArr.length - 1).join('-');
        if (curNodeParentcode === parentcode) {
            tree.push(p);
            p.children = toTree(arr, p.code);
        }
    });
    return tree;
}