Ember provides several configuration options that can help you debug problems
with your application.

## Routing

#### Log router transitions

```javascript {data-filename=app/app.js}
import Ember from 'ember';

export default Ember.Application.extend({
  // Basic logging, e.g. "Transitioned into 'post'"
  LOG_TRANSITIONS: true,

  // Extremely detailed logging, highlighting every internal
  // step made while transitioning into a route, including
  // `beforeModel`, `model`, and `afterModel` hooks, and
  // information about redirects and aborted transitions
  LOG_TRANSITIONS_INTERNAL: true
});
```
## Views / Templates

#### Log view lookups

```javascript {data-filename=config/environment.js}
ENV.APP.LOG_VIEW_LOOKUPS = true;
```
#### View all registered templates
```javascript
Ember.keys(Ember.TEMPLATES)
```

## Controllers

#### Log generated controller

```javascript {data-filename=config/environment.js}
ENV.APP.LOG_ACTIVE_GENERATION = true;
```

## Observers / Binding

#### See all observers for an object, key

```javascript
Ember.observersFor(comments, keyName);
```

#### Log object bindings

```javascript {data-filename=config/environments.js}
ENV.APP.LOG_BINDINGS = true
```

## Miscellaneous

#### Turn on resolver resolution logging

This option logs all the lookups that are done to the console. Custom objects
you've created yourself have a tick, and Ember generated ones don't.

It's useful for understanding which objects Ember is finding when it does a lookup
and which it is generating automatically for you.

```javascript {data-filename=app/app.js}
import Ember from 'ember';

export default Ember.Application.extend({
  LOG_RESOLVER: true
});
```
#### Dealing with deprecations

```javascript
Ember.ENV.RAISE_ON_DEPRECATION = true
Ember.ENV.LOG_STACKTRACE_ON_DEPRECATION = true
```


#### Implement an Ember.onerror hook to log all errors in production

```javascript
Ember.onerror = function(error) {
  Ember.$.ajax('/error-notification', {
    type: 'POST',
    data: {
      stack: error.stack,
      otherInformation: 'exception message'
    }
  });
}
```

#### Import the console

If you are using imports with Ember, be sure to import the console:

```javascript
Ember = {
  imports: {
    Handlebars: Handlebars,
    jQuery: $,
    console: window.console
  }
};
```

#### Errors within an `RSVP.Promise`

There are times when dealing with promises that it seems like any errors
are being 'swallowed', and not properly raised. This makes it extremely
difficult to track down where a given issue is coming from. Thankfully,
`RSVP` has a solution for this problem built in.

You can provide an `onerror` function that will be called with the error
details if any errors occur within your promise. This function can be anything,
but a common practice is to call `console.assert` to dump the error to the
console.

```javascript {data-filename=app/app.js}
import Ember from 'ember';
import RSVP from 'rsvp';

RSVP.on('error', function(error) {
  Ember.Logger.assert(false, error);
});
```

#### Errors within `Ember.run.later` ([Backburner.js](https://github.com/ebryn/backburner.js))

Backburner has support for stitching the stacktraces together so that you can
track down where an erroring `Ember.run.later` is being initiated from. Unfortunately,
this is quite slow and is not appropriate for production or even normal development.

To enable this mode you can set:

```javascript
Ember.run.backburner.DEBUG = true;
```