AngularJS 1.7.9 : how to debug “Possibly unhandled rejection: {}”?

问题

I am aware of siiar questions, such as Angularjs 1.7.9 - Possibly unhandled rejection and those mentioned in it as duplicates.

However, my code does not use promises (that I am aware of; certainly no $promise or $http).

I am just knocking up a simple ui-router demo for a friend. It is just two views, each with a button that toggles to the other view. It works just fine with AngulrJs 1.5, and breaks with the above error in 1.7.

A simple as it is, it's a bit too much code to post. In case, rather than finding the error in my code, I woudl like a canonical answer to help others who read this question in future : how to go about denugging this error message?

Error: transition failed (caused by "Possibly unhandled rejection: {}")

at r [as $get] (http://localhost/common/js/third_party/ui-router_zero_pint_2_point_11/angular-ui-router.min.js:7:11365)  
at Object.invoke (http://localhost/common/js/third_party/angular-1_point_7_point_9/angular.min.js:45:62)  
at http://localhost/common/js/third_party/angular-1_point_7_point_9/angular.min.js:46:365  
at d (http://localhost/common/js/third_party/angular-1_point_7_point_9/angular.min.js:43:495)  
at e (http://localhost/common/js/third_party/angular-1_point_7_point_9/angular.min.js:44:235)  
at Object.invoke (http://localhost/common/js/third_party/angular-1_point_7_point_9/angular.min.js:44:320)  
at http://localhost/common/js/third_party/angular-1_point_7_point_9/angular.min.js:47:18  
at r (http://localhost/common/js/third_party/angular-1_point_7_point_9/angular.min.js:8:76)  
at fb (http://localhost/common/js/third_party/angular-1_point_7_point_9/angular.min.js:46:499)  
at c (http://localhost/common/js/third_party/angular-1_point_7_point_9/angular.min.js:22:57)

回答1:

The latest version of UI-router (1.0.25) solved the problem. Feel free to post an answer.

You will get a more informative stack trace if you use angular.js instead of angular.min.js and angular-ui-router.js instead of angular-ui-router.min.js. Angular-UI-Router uses promises in its transition module. It looks like you upgraded your version of AngularJS without upgrading the version of Angular-UI-Router. Upgrade your router from V0.2.11 to V0.4.3. It looks like your problem is caused by sloppy Angular-UI-Router code. If they didn't fix the issue by V0.4.3, you can either patch the library or live with the messages.

Debugging `"possibly unhandled rejection"`

The stack trace will show the file and the line number from which the error originates. Examine the code and fix the problem. If the error orginates in a third- party library, try upgrading to the latest version or contacting the third-party library vendor.

As a last resort, disable the "possibly unhandled rejection" messages:

app.config(functon ($qProvider) {
    $qProvider.errorOnUnhandledRejections(false);
});

This is not recommended as it allows other problems to silently fail.

If one doesn't care about a specific promise failing, add a .catch handler:

$http(config).then(function(response) {
    //...
}).catch(function(response) {
   //I don't care about errors
   if (debug) console.log(response);
   //Re-throw error response
   throw response;
})

Upgrading AngularJS

When upgrading AngularJS, it is best to upgrade all of the AngularJS modules at the same time. That is when migrating from angular.js@1.4 to angular.js@1.5, at the same time upgrade to angular-animate@1.5, angular-resource@1.5, angular-route.js@1.5, etc. I have seen unpleasant problems when trying to mix and match versions of AngularJS modules.

When migrating, I recommend upgrading one minor version at a time. For example, upgrade from V1.4 to V1.5 first, fix what breaks, then upgrade to V1.6.

The current version is 1.7.9 pollution-eradication (2019-11-19). I recommend using the latest version as the AngularJS team has committed to fixing security bugs only in both V1.2.x and the latest version. For more information, see

AngularJS Developer Guide - Migrating from Previous Versions
AngularJS Version Support Status - Long Term Support

Upgrading Angular-UI-Router

UI-Router for AngularJS has two major versions

Version 0.4.3 UI-Router-Legacy

Version 1.0.25 UI-Router for AngularJS

I recommend upgrading to the latest version of UI-Router-Legacy before migrating to the latest version of UI-Router for AngularJS. There have been major breaking changes between the two and it is best to deal with it incrementally.

For more informaton, see

Angular-UI Guide: UI-Router 1.0 Migration

回答2:

One way to debug ui-router is the following:

From the console inject the $state service typing the following:

var test = angular.element(document.body).injector().get('$state');

Then simulate and perform the transition that causes the problem:

test.go('root.details') // use the state url here

After that, details of the transition will be printed in console. Into $$state object, you may find more details about the failed transition and reasons of failure:

来源：https://stackoverflow.com/questions/60350813/angularjs-1-7-9-how-to-debug-possibly-unhandled-rejection

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