将扁平结构转换为树形结构在前端开发的过程中免不了要处理各种展示树结构的场景，后端往往是返回一整个列表让前自己处理，这里我基于 JS 和 TS 分别实现了此功能JavaScriptconst sourceList = [ { id: 1, name: 'A', parent_id: null }, { id: 2, name: 'B', parent_id: 1 }, { id: 3, name: 'C', parent_id: 1 }, { id: 4, name: 'D', parent_id: 2 }, { id: 5, name: 'E', parent_id: 2 }, { id: 6, name: 'F', parent_id: 3 }, ]; function buildTree(sourceList, parent_id = null) { const treeList = []; for (const item of sourceList) { if (parent_id === item.parent_id) {