我试图在搜索过程之后得到一个树节点。但是它总是返回未定义的。 这是代码。
const findOrder = (list, key) =>
new Promise((resolve) => {
for (let i = 0; i < list.length; i++) {
// find node through key in tree
if (list[i].key === key) {
console.log(`================I got it!: `, list[i].children); // children[]
resolve(list[i].children);
}
if (list[i].children) {
findOrder(list[i].children, key);
}
}
});
const setOrder = async() => {
const orders = await findOrder(
treeData,
dropObj.classKind === "1" ? keyGen(dropObj.key) : dropObj.key
);
console.log(`==================siblings: `, orders); // undefined
};
setOrder();
出什么问题了?
答案 0 :(得分:1)
您在这里没有解决问题,
// ...
if (list[i].children) {
findOrder(list[i].children, key);
}
// ...
要让外部Promise知道何时解决它,您应该明确地做到这一点:
// ...
if (list[i].children) {
findOrder(list[i].children, key).then(result => {
// as resolve can only be called once,
// do not call it if it doesn't found anything
if (result) resolve(result)
});
}
// ...
这应该有效。但是,此实现有太多无用的“解析”调用。最好直接找到匹配的项目并解决它。
这里是一个例子:
const findOrder = function (list, key) {
return new Promise((resolve, reject) => {
resolve(find(list, key))
function find (_list, key) {
for (let i = 0; i < _list.length; i++) {
if (_list[i].key === key) return _list[i].children
if (_list[i].children) {
const c = find(_list[i].children, key)
if (c) return c
}
}
return undefined
}
})
}