Promisereactionjob safari error

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Promisereactionjob Safari Error

Safari browser has a known issue with the JavaScript promise method PromiseReactionJob. This error typically occurs when using promises incorrectly and can lead to unexpected behavior or even crashes in Safari.

Example:

Let’s say we have the following JavaScript code:


    let promise = new Promise((resolve, reject) => {
      // Some asynchronous operation
      // Simulating an error here
      throw new Error('Something went wrong');
    });
    
    promise.catch(error => {
      console.error(error);
    });

In most modern browsers, including Chrome and Firefox, this code will correctly catch the error and log it to the console. However, in Safari, it will throw an additional PromiseReactionJob error.

This happens because Safari’s JavaScript engine handles promises differently. When a promise is rejected, Safari tries to schedule a “reaction job” to handle the rejection. In the above example, since the error is thrown synchronously, Safari encounters the PromiseReactionJob error.

Solution:

To fix this issue, you need to ensure that promises are always rejected asynchronously, even if the error occurs synchronously. One common approach is to use setTimeout to delay the rejection, like this:


    let promise = new Promise((resolve, reject) => {
      setTimeout(() => {
        // Some asynchronous operation
        // Simulating an error here
        try {
          throw new Error('Something went wrong');
        } catch (error) {
          reject(error);
        }
      }, 0);
    });
    
    promise.catch(error => {
      console.error(error);
    });

By wrapping the code in setTimeout, the error is thrown inside a new event loop iteration, making it asynchronous and avoiding the PromiseReactionJob error in Safari.

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