asyncErrorHandling.js

'use strict';

//error is caught by the promise
function someSyncFunctionThrow(){
    let promise = new Promise((resolve, reject)=>{
        throw 'someSyncFunctionThrow error occurred!!!!';
        resolve();
    });
    return promise;
}
someSyncFunctionThrow().then(()=>{}).catch(err=>{ console.error(`Promise.catch -- error someSyncFunctionThrow: ${err}`)});

//error is caught by the promise
function someSyncFunctionReferrenceError(){
    let promise = new Promise((resolve, reject)=>{
        asdf.x();
        resolve();
    });
    return promise;
}
someSyncFunctionReferrenceError().then(()=>{}).catch(err=>{console.error(`Promise.catch -- error someSyncFunctionReferrenceError ${err}`)});

//error is NOT caught by the promise.
function someAsyncFunctionThrow(){
    let promise = new Promise((resolve, reject)=>{
        setTimeout(()=>{
            throw 'someAsyncFunctionThrow error occurred!!!!';
            resolve();
        },0);
    });
    return promise;
}
someAsyncFunctionThrow().then(()=>{}).catch(err=>{ console.error(`Promise.catch -- error someAsyncFunctionThrow: ${err}`)});

//error is NOT caught by the promise
function someAsyncFunctionReferenceError(){
    let promise = new Promise((resolve, reject)=>{
        setTimeout(()=>{
            asdf.asdf();
            resolve();
        },0);
    });
    return promise;
}
someAsyncFunctionReferenceError().then(()=>{}).catch(err=>{console.error(`Promise.catch -- someAsyncFunctionReferenceError reference error ${err}`)});


//error is NOT caught by try catch.
function nonPromiseAsyncThrowWithCatchOutside(){
    try{
        setTimeout(()=>{
            throw 'nonPromiseAsyncThrow error occurred!!!!';
        },0)
    }catch(e){
        console.error(`catch caught exception ${e}`);
    }

}
nonPromiseAsyncThrowWithCatchOutside();

//error is caught
function nonPromiseAsyncThrowWithCatchInside(){

    setTimeout(()=>{
        try{
            throw 'nonPromiseAsyncThrow error occurred!!!!';
        }catch(e){
            console.error(`catch caught exception ${e}`);
        }
    },0);

}
nonPromiseAsyncThrowWithCatchInside();



//error is caught by promise
function someAsyncFunctionReferenceErrorWithTryCatch(){
    let promise = new Promise((resolve, reject)=>{
        setTimeout(()=>{
            try{
                asdf.asdf();
                resolve();
            }catch(e){
                reject(e);
            }

        },0);
    });
    return promise;
}
someAsyncFunctionReferenceErrorWithTryCatch().then(()=>{}).catch(err=>{console.error(`Promise.catch -- someAsyncFunctionReferenceErrorWithTryCatch reference error ${err}`)});


process.on('uncaughtException', (err) => {
    console.log(`Process Caught exception: ${err}`);
});

process.on('unhandledRejection', (reason, p) => {
    console.log(`Process unhandledRejection ${reason}`);
});
process.on('rejectionHandled', (p) => {
    console.log(`Process rejection handled`);
});

Result:

Promise.catch -- error someSyncFunctionThrow: someSyncFunctionThrow error occurred!!!!
Promise.catch -- error someSyncFunctionReferrenceError ReferenceError: asdf is not defined
Process Caught exception: someAsyncFunctionThrow error occurred!!!!
Process Caught exception: ReferenceError: asdf is not defined
Process Caught exception: nonPromiseAsyncThrow error occurred!!!!
catch caught exception nonPromiseAsyncThrow error occurred!!!!
Promise.catch -- someAsyncFunctionReferenceErrorWithTryCatch reference error ReferenceError: asdf is not defined