AggregateError Combine Multiple Errors Into Single

In this tutorial, we will see about the AggregateError in which we can combine the multiple errors into a single error instance.

AggregateError

The error is thrown when there is a possibility of multiple errors to be reported. AggregateError object takes multiple iterable Error instances and wraps them in a single error.

Syntax

AggregateError(Array<Error>, "message");

How to throw an AggregateError

The way we throw the errors like Error, TypeError In a similar way we can throw this error.

throw new AggregateError([
    new Error("Required field are missing"),
    new TypeError("Typeof error for Status field"),
], "Common Error Message for your operation");

How to catch and show an Error

If the error type is of instanceof AggregateError then it will contain the error message and an array of errors.

try {
    throw new AggregateError([
        new Error("Required field are missing"),
        new TypeError("Typeof error for Status field"),
    ], "Common Error Message for your operation");
} catch(e) {
    console.log(e instanceof AggregateError); //true
    console.log(e.message)
    //Common Error Message for your operation

    console.log(e.name)
    //AggregateError

    console.log(e.errors);
    // [Error: "Required field are missing", Error: "Typeof error for Status field"]
}

Usage / Use Cases

• During Promise.all or Promise.any all errors from all async operations will be caught with one error object. It can help you to provide detailed error messages.
• If you are a backend or API developer, you can collect all the validation errors or expectations in an array and report it once.
  It makes easy by instantiating one object for each request and lets you collect many errors from ACLs, Authentication, Validation, etc.
• Using this you do not have to stop the execution in the middle of the process and skip the other part by throwing an error object. All you can do is pass or collect an Error in an array object and finally deal with the errors if at all required.