rethrow.js
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/**
`rethrow` will rethrow an error on the next turn of the JavaScript event
loop in order to aid debugging.
Promises A+ specifies that any exceptions that occur with a promise must be
caught by the promises implementation and bubbled to the last handler. For
this reason, it is recommended that you always specify a second rejection
handler function to `then`. However, `rethrow` will throw the exception
outside of the promise, so it bubbles up to your console if in the browser,
or domain/cause uncaught exception in Node. `rethrow` will also throw the
error again so the error can be handled by the promise per the spec.
```javascript
import { rethrow } from 'rsvp';
function throws(){
throw new Error('Whoops!');
}
let promise = new Promise(function(resolve, reject){
throws();
});
promise.catch(rethrow).then(function(){
// Code here doesn't run because the promise became rejected due to an
// error!
}, function (err){
// handle the error here
});
```
The 'Whoops' error will be thrown on the next turn of the event loop
and you can watch for it in your console. You can also handle it using a
rejection handler given to `.then` or `.catch` on the returned promise.
@method rethrow
@public
@static
@for rsvp
@param {Error} reason reason the promise became rejected.
@throws Error
@static
*/
export default function rethrow(reason) {
setTimeout(() => {
throw reason;
});
throw reason;
}