我正在使用环绕其 API 的第 3 方模块。我有以下代码:
const api = require('3rdpartyapi');
async function callAPI(params) {
try {
let result = await api.call(params);
return result;
}
catch(err) {
throw err; //will handle in other function
}
}
async function doSomething() {
try {
//...do stuff
let result = await callAPI({a:2,b:7});
console.log(result);
}
catch(err) {
console.error('oh no!', err);
}
}
尽管 try
-catch
block ,第 3 方 API,当它失去与 homebase 的连接时(经常发生 :( ),爆炸:
(node:13128) UnhandledPromiseRejectionWarning: FetchError: request to https://www.example.com failed, reason: getaddrinfo ENOTFOUND
其次是:
UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
为什么我的 try
-catch
都没有捕捉到这个?到底什么是未处理的,如何实际处理?
最佳答案
关键是 await 只将“第一层”拒绝转换为错误,但是 promise 可以在里面有 promise,他们的库可能无法捕获里面的拒绝。我已经制作了一个概念证明 3rdpartyapi,它可以触发您看到的行为:
(async function () {
// mock 3rdpartyapi
var api = {
call: async function(){
await new Promise((resolve, reject) => {
// why wrap a promise here? but i don't know
new Promise((innerResolve, innerReject) => {
innerReject('very sad'); // unfortunately this inner promise fail
reject('this sadness can bubble up');
})
})
}
};
// your original code
async function callAPI(params) {
try {
let result = await api.call(params);
return result;
} catch (err) {
throw err; //will handle in other function
}
}
async function doSomething() {
try {
//...do stuff
let result = await callAPI({
a: 2,
b: 7
});
console.log(result);
} catch (err) {
console.error('oh no!', err);
}
}
doSomething();
})();
输出:
$ node start.js
oh no! this sadness can bubble up
(node:17688) UnhandledPromiseRejectionWarning: very sad
(node:17688) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:17688) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
关于javascript - 尽管有几个 `try` -`catch` block ,但获取 UnhandledPromiseRejectionWarning,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/54699731/