$q.all will return a resolved promise as long as there is at least one rejected

Question

$q.all will return a resolved promise as long as there is at least one rejected

I am attempting to run multiple promises simultaneously so that I can perform a task once they have all resolved. Even though there is a rejected promise, '$q.all()' still resolves. Am I missing something in the behavior of '$q.all'?

Appreciate any help on this issue!

        function saveOrder () {

            return ordersSrv.saveOrder(order).then(function(data) {

                console.log('saveOrder OK');
            },
            function(error) {

                console.log('saveOrder KO');
            });
        }


        var aPromises = [saveOrder()];

        $q.all(aPromises).then(function () {

            console.log('OK');

        },
        function (error) {
            console.log('---> error');
        });

javascript angularjs promise

Answer 1

Answer №1

When you encounter an error in a try catch block and do not rethrow it, the error is considered handled:

try {
   throw Error();
} catch (e) {
    console.log("Error", e);
}
console.log("This statement will also be executed");

The same concept applies to promises:

Promise.reject(Error())
  .catch(e => console.log("Error", e))
  .then(() => console.log("This statement will also be executed"));

If you want to handle the error, make sure to add a catch handler when rejecting with saveError. To log the error but still not handle it, rethrow it:

try {
   throw Error();
} catch (e) {
    console.log("Error", e);
    throw e;
}
console.log("This statement will not be executed");

Similarly with promises:

Promise.reject(Error())
  .catch(e => { console.log("Error", e); throw e; })
  .then(() => console.log("This statement will not be executed"));

Answer 2

When you encounter an error in a try catch block and do not rethrow it, the error is considered handled:

try {
   throw Error();
} catch (e) {
    console.log("Error", e);
}
console.log("This statement will also be executed");

The same concept applies to promises:

Promise.reject(Error())
  .catch(e => console.log("Error", e))
  .then(() => console.log("This statement will also be executed"));

If you want to handle the error, make sure to add a catch handler when rejecting with saveError. To log the error but still not handle it, rethrow it:

try {
   throw Error();
} catch (e) {
    console.log("Error", e);
    throw e;
}
console.log("This statement will not be executed");

Similarly with promises:

Promise.reject(Error())
  .catch(e => { console.log("Error", e); throw e; })
  .then(() => console.log("This statement will not be executed"));

$q.all will return a resolved promise as long as there is at least one rejected

Answer №1

Similar questions

Tips for concealing an element with Clippy.js without relying on a timeout feature

Ways to verify that a javascript function generates an object and executes a method within that object

Node.js dynamically updates exports for efficient code execution

Which is better for your website: SSG vs SSR?

What is the best way to divide a range of numbers between m and n using JavaScript

Generate a JSON Object array by collecting data from various elements to make it dynamic

Challenges Encountered with jQuery/AJAX Form Processing

The issue of resolving NestJs ParseEnumPipe

Transform for loop from Axios post requests to promises

Sync jQuery resizable resizing

Encountering a npm error E404 when trying to install unicons package for React development

Controlling dropdown menus filled with AJAX responseData

What could be causing my JavaScript code to not function properly in an HTML document?

Trouble with React routes: only fixed after refreshing the page

JavaScript onclick event ceases to function after initial click

Controlling the display and status of DIV elements as radio button choices within a React application

Express.js encountered an unexpected token symbol "<"

establish a connection with the node server and initiate the automatic mask detection feature

Processing two Array Objects can be achieved without resorting to the EVAL function

Verifying the presence of an image via its URL may not be functional across all browsers