Add a useRawError option to have the raw error object be passed to the error callback

Author: foxbenjaminfox

Diff for: README.md

@@ -204,21 +204,33 @@ new Vue({
 
 By default, in case of a rejected promise in an async computed property, vue-async-computed will take care of logging the error for you.
 
-If you want to use a custom logging function, the plugin takes an `errorHandler` option, which should be the function you want called with the error information.
+If you want to use a custom logging function, the plugin takes an `errorHandler` option, which should be the function you want called with the error information. By default, it will be called with the error's stack trace as an argument, but if you want the raw error itself you can set the
+`useRawError` option to `true`.
 
 For example: 
 
 ````js
 Vue.use(AsyncComputed, {
-  errorHandler (msg) {
+  errorHandler (stack) {
     console.log('Hey, an error!')
     console.log('---')
-    console.log(msg)
+    console.log(stack)
+  }
+)
+
+// Or with `useRawError`:
+Vue.use(AsyncComputed, {
+  useRawError: true,
+  errorHandler (err) {
+    console.log('An error occurred!')
+    console.log('The error message was: ' + err.msg)
+    console.log('And the stack trace was:')
+    console.log(err.stack)
   }
 )
 ````
 
-You can pass `false` in order to silently ignore rejected promises.
+You can pass `false` as the `errorHandler` in order to silently ignore rejected promises.
 
 ## License
 

Diff for: src/index.js

@@ -51,7 +51,11 @@ const AsyncComputed = {
                 ? console.error.bind(console, 'Error evaluating async computed property:')
                 : options.errorHandler
 
-              handler(err.stack)
+              if (options.useRawError) {
+                handler(err)
+              } else {
+                handler(err.stack)
+              }
             })
           }, { immediate: true })
         })

Diff for: test/index.js

@@ -9,6 +9,7 @@ let baseErrorCallback = () => {
 let testErrorCallback = baseErrorCallback
 
 Vue.use(AsyncComputed, {
+  useRawError: true,
   errorHandler: msg => testErrorCallback(msg)
 })
 
@@ -155,17 +156,18 @@ test("Having only sync computed data still works", t => {
 })
 
 test("Handle errors in computed properties", t => {
-  t.plan(2)
+  t.plan(3)
   const vm = new Vue({
     asyncComputed: {
       a () {
-        return Promise.reject("error")
+        return Promise.reject('error')
       }
     }
   })
   t.equal(vm.a, null)
-  testErrorCallback = msg => {
+  testErrorCallback = err => {
     t.equal(vm.a, null)
+    t.equal(err, 'error')
     testErrorCallback = baseErrorCallback
   }
 })