英文:
Caught error still trigger `.catch` method for Promises
问题
My problem
我有一个异步方法 populate()，它尝试执行某些操作，如果失败，则捕获错误并调用另一个异步方法 populateFromServer()（它也可能失败）。
我在 Promise.all() 中调用第一个方法，然后在没有任何尝试成功的情况下使用 catch。然而，由于某种原因，.all() 始终会因为 populate() 而触发，尽管应该被捕获。
以下是我的代码的简化版本（typescript）：
abstract class Database {
public static async populate() {
try {
await populateFromLocalFile();
} catch (err) {
await this.populateFromServer();
}
}
private static async populateFromServer() {
await fetchFromServer(); // 可能失败，例如如果没有网络
}
}
还有其他地方的代码：
Promise.all([
ChildDB1.populate(),
ChildDB2.populate(),
ChildDB3.populate(),
])
.then(() => /* 数据填充成功（本地或远程） */)
.catch(() => /* 没有任何尝试成功 */)
尽管我已经捕获了 populate() 的失败，并且 populateFromServer() 也正常工作（我通过日志进行了检查），但我的代码似乎在 Promise.all 后被捕获。为什么？如何修复这个问题？
What I tried
Returning Promise.resolve()
有人建议在 catch 块的末尾返回 Promise.resolve()，但这并没有解决问题：
public static async populate() {
try {
await populateFromLocalFile();
} catch (err) {
await this.populateFromServer();
return Promise.resolve()
}
return Promise.resolve()
}
Using .then
我还尝试使用 .then 的方式，但问题仍然存在：
abstract class Database {
public static async populate() {
await populateFromLocalFile()
.then(() => doStuff())
.catch(async () => {
console.log('error happened here');
await this.populateFromServer();
});
}
private static async B() {
await fetchFromServer();
}
}
英文:
My problem
I have an asynchronous method populate() that tries to do something, and if it fails, catches the error and calls another asynchronous method populateFromServer() (which can fail too).
I call the first in a Promise.all() with a catch afterwards in case no attempt worked. However, .all() always trigger because of populate(), for some reason, although it should be caught.
Here is a simplified version of my code (typescript):
abstract class Database {
public static async populate() {
try {
await populateFromLocalFile();
} catch (err) {
await this.populateFromServer();
}
}
private static async populateFromServer() {
await fetchFromServer(); // Might fail eg. if there is no internet
}
}
And somewhere else:
Promise.all([
ChildDB1.populate(),
ChildDB2.populate(),
ChildDB3.populate(),
])
.then(() => /* population worked (either local or distant) */)
.catch(() => /* no population attempt worked */)
My code seems to get caught after the Promise.all when populate() fails, even though I caught it and populateFromServer() worked perfectly fine (I checked with logs). Why? How can I fix that?
What I tried
Returning Promise.resolve()
Someone suggested to return Promise.resolve() at the end of the catch block, but it doesn't fix the problem:
public static async populate() {
try {
await populateFromLocalFile();
} catch (err) {
await this.populateFromServer();
return Promise.resolve()
}
return Promise.resolve()
}
Using .then
I also tried using the other way with .then but I still have that problem
abstract class Database {
public static async populate() {
await populateFromLocalFile()
.then(() => doStuff())
.catch(async () => {
console.log('error happened here');
await this.populateFromServer();
});
}
private static async B() {
await fetchFromServer();
}
}
答案1
得分: 0
代码部分不要翻译
The problem was in the .then method of my Promise.all
Promise.all([
ChildDB1.populate(),
ChildDB2.populate(),
ChildDB3.populate(),
])
.then(() => /* stuff */) // <-- this is the part that failed silently
.catch(() => /* other stuff */)
英文:
The problem was in the .then method of my Promise.all
Promise.all([
ChildDB1.populate(),
ChildDB2.populate(),
ChildDB3.populate(),
])
.then(() => /* stuff */) // <-- this is the part that failed silently
.catch(() => /* other stuff */)
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论