node.js catch block not firing as expected on await - node.js

Question

My node process exited after logging
E callback: [Function: RP$callback],
E { serviceName: '....',
E errno: 'EAI_AGAIN',
E name: 'RequestError',
But I thought the below code would catch exceptions and return the defaulted value
var rp = require('request-promise');
async function verifyJWT(jwt: string): Promise<any> {
const userDataPromise = rp({
uri: ...,
method: 'POST',
json: {
...
}
});
const userData = await userDataPromise.catch((err: any) => {
console.error(`verifyJWT: err`, err)
return {
authInfo: {}
};
});
return userData;
}
export default verifyJWT
Are there certain types of failures that would not get caught here?
Would it be better to provide a rejection handler in catch on the promise?
Thanks,
Brent

Answer 1

You're mixing standard promise handling with async/await style promise handling. You should try to use one or the other, but not both. Using both methods simultaneously is not restricted, but it certainly adds confusion.
This is what async/await style promise handling should look like:
async function verifyJWT(jwt: string): Promise<any> {
try {
return await rp({
uri: ...,
method: 'POST',
json: {
...
}
});
} catch (err) {
console.error(`verifyJWT: err`, err);
return {
authInfo: {}
};
}
}
This is what standard promise handling should look like:
function verifyJWT(jwt: string): Promise<any> {
return rp({
uri: ...,
method: 'POST',
json: {
...
}
}).catch((err: any) => {
console.error(`verifyJWT: err`, err);
return {
authInfo: {}
};
});
}

Answer 2

You aren't using async await as it should be used
async await enables the code to wait for promise response and then move on to the next step. Any error returned by the rest endpoint, is caught by the catch block.
i've posted a sample code below, to show how async await would work with promise
var rp = require('request-promise');
var myfun = async ()=>{
let returnValue = null;
try{
let response = await rp("http://localhost:3000/getdata");
console.log("ajax success");
returnValue = response;
}
catch(err){
console.log("ajax error ",err.message)
returnValue = err.message;
}
return returnValue;
}
Note if you want to return any data from async function, then the calling function should also be async and await has to be used while invoking.
Read more about async await