# Lazy Single (Leaf Only) ```html ``` ```js function genChildren (option) { const children = [] const label = option.label || 'root' for (let i = 0; i <= option.depth; ++i) { children.push({ label: label + '_' + i, value: label + '_' + i, isLeaf: option.depth === 3 }) } return children } export default { data () { return { value: null } }, methods: { handleLoad (option, resolve) { window.setTimeout(() => { resolve(genChildren(option)) }, 1000) } } } ```