CODEWITHSUNDEEP
javascriptpromise
Gayathri
Gayathri

Reputation: 1896

Unhandled rejection - Promise

I am new to UnhandledRejection. The below method is supposed to throw exception and terminate flow but it doesn't.Please favour on resolving it either way

Case 1: Took value from promise as true and tried conditions.But it is bypassed and returns unhandled rejection with the exception to be thrown.

Utils.isMaximumLimitReached(id).then(isLimit=>{
    console.log(isLimit); //true
    if(isLimit){
       throw "not allowed";
    }
  })

Edit: Case 3:This too returns Unhandled rejection this is not allowed

const isMaximumLimitReached = coachingId => {
  return db.coachingClassEntries
    .findAndCountAll()
    .then(counts => {
      let numberOfEntries = 2;
      //let maxEntries = counts.rows[0].coachingClass.maxEntries;
      let maxEntries=2;
      return new Promise((resolve,reject)=>{
        if (numberOfEntries == maxEntries) {
           reject('this is not allowed');
      }
      });

    });
};

  Utils.isMaximumLimitReached(data.coachingClassId).then().catch(error=>{
       throw error;
   })

Upvotes: 1

Views: 1683

Answers (2)

Rohan Kadu
Rohan Kadu

Reputation: 1389

Change your Promise.reject with

Promise.reject(new Error('409',msg)).then(function() {
  // not called
}, function(error) {
  console.log(error); // Stacktrace
});

Hope this helps and resolve your issue. And If you want to throw the error then you check this before deciding what to use.

Upvotes: 1

S.B.
S.B.

Reputation: 2969

Promise rejections are usually handled with a second callback in the then method, which could look like this in your case 1:

Utils.isMaximumLimitReached(id).then(()=>{
  // everything is fine
}, (error) => {
  // promise was rejected, handle error
  console.log(error);
})

This way, any rejections caused by isMaximumLimitReached will be handled in the error callback.

Upvotes: 1

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