Error message: An undefined error occurred in the uncaught promise of an async function

Question

Error message: An undefined error occurred in the uncaught promise of an async function

Before creating or updating an entry, I am performing validations using the code snippet below:

async save(){
      return new Promise((resolve, reject)=>{
        if(!this.isCampaignValid){
          this.handleError()
          reject()
        }
        else{
          this.$store
            .dispatch('updateCampaign')
            .then((res)=>{
              resolve()
              this.showNotification(res.message, 'success')
            })
            .catch(error=>{
              this.showNotification(error.message, 'error')
              reject()
            })
        }
      })
    },

The validity of the campaign is determined by the computed value isCampaignValid.

If the campaign is not valid, an error message appears in the console:

Uncaught (in promise) undefined

The function this.handleError() is also executed. How can I handle this promise error situation effectively?

javascript vue.js

Answer 1

Answer №1

If there is a possibility that handleError() may throw an error, consider using the following approach:

if (!isValidCampaign()) {
  try {
    handleError()
  } catch (error) {
    console.log(error);
  }
  rejectPromise()
}

Answer 2

If there is a possibility that handleError() may throw an error, consider using the following approach:

if (!isValidCampaign()) {
  try {
    handleError()
  } catch (error) {
    console.log(error);
  }
  rejectPromise()
}

Answer 3

Answer №2

First things first, there's no need to explicitly return a promise in an async function. The function automatically returns a promise, resolved with the value returned by the function or rejected with an error object if the function encounters an error. While it is possible to return a promise, JavaScript handles it internally, making it unnecessary extra code.

However, since an async function returns a promise, you must also handle that promise. In your initial conditional block, where you throw an error without catching it, the promise returned by save will be rejected. It's crucial to manage this rejection properly.

Below is a simplified version of your code highlighting where the issue arises.

async save() {
    if (!this.isCampaignValid) {
        this.handleError();
        // Throwing an error in an async function is akin to rejecting.
        throw new Error('Campaign is not valid'); // This line here
    } else {
        try {
            const res = await this.$store.dispatch('updateCampaign');
            this.showNotification(res.message, 'success');
        } catch (error) {
            this.showNotification(error.message, 'error');
        }
    }
}

// When you invoke save, ensure to handle errors
yourObject.save()
  .then(() => {...})
  .catch(() => {...})

// If save is called within an async function, you can also use try-catch
try {
  await yourObject.save();
} catch (e) {
  // Handling failure scenario
}

Answer 4

First things first, there's no need to explicitly return a promise in an async function. The function automatically returns a promise, resolved with the value returned by the function or rejected with an error object if the function encounters an error. While it is possible to return a promise, JavaScript handles it internally, making it unnecessary extra code.

However, since an async function returns a promise, you must also handle that promise. In your initial conditional block, where you throw an error without catching it, the promise returned by save will be rejected. It's crucial to manage this rejection properly.

Below is a simplified version of your code highlighting where the issue arises.

async save() {
    if (!this.isCampaignValid) {
        this.handleError();
        // Throwing an error in an async function is akin to rejecting.
        throw new Error('Campaign is not valid'); // This line here
    } else {
        try {
            const res = await this.$store.dispatch('updateCampaign');
            this.showNotification(res.message, 'success');
        } catch (error) {
            this.showNotification(error.message, 'error');
        }
    }
}

// When you invoke save, ensure to handle errors
yourObject.save()
  .then(() => {...})
  .catch(() => {...})

// If save is called within an async function, you can also use try-catch
try {
  await yourObject.save();
} catch (e) {
  // Handling failure scenario
}

Error message: An undefined error occurred in the uncaught promise of an async function

Answer №1

Answer №2

Similar questions

How to prevent uncaught errors when checking for undefined in if statements and dealing with undefined items

Troubleshooting a Dysfunctioning Character Counter Feature in a JavaScript Input Field

Stripping away AM | PM from date variables

Encountering an Axios Error 404 while attempting to save my information to the MongoDB database

Adding various textures to an obj file

Issue with 'typename' in Vue Apollo's updateQuery causing undefined behavior

Encountering an error due to a missing property while trying to

Exploring logfile usage in JavaScript. What is the best way to structure the log?

Is there a way to customize Angular's number filter?

Tips for creating a multi-step wizard using AngularJS and incorporating AJAX calls---Crafting a multi

Integrate UploadFS functionality into angular2-meteor

Compress and condense AngularJS Source Code without using NodeJS

"Seeking guidance on getting my carousel functionality up and running in Angular 8 - any

Transmitting variable parameters to the server, including the possibility of numerical fluctuations

Is it possible to add a vertical scrollbar to the vertical navigation pills on a Bootstrap

The 'fn' argument passed is not a valid function, instead it is a string

Obtain the jQuery dialog's closure event within the $.Ajax completion function

Can a frontend framework be exclusively utilized on a single page within a completed project?

Switching the default port for a Vue.js application running in a Docker container

Stanza.io encountered difficulties in generating a WebRTC answer