fix(vue-app): allow passing custom props to error function (#4462)

Resolves #4460.

packages/vue-app/template/utils.js

@@ -285,6 +285,7 @@ export function normalizeError(err) {
     message = err.message || err
   }
   return {
+    ...err,
     message: message,
     statusCode: (err.statusCode || err.status || (err.response && err.response.status) || 500)
   }

test/e2e/basic.browser.test.js

@@ -166,7 +166,7 @@ describe('basic browser', () => {
     await page.nuxt.navigate('/error2')
 
     expect(await page.$text('.title')).toBe('Custom error')
-    expect(await page.nuxt.errorData()).toEqual({ message: 'Custom error', statusCode: 500 })
+    expect(await page.nuxt.errorData()).toEqual({ message: 'Custom error', statusCode: 500, customProp: 'ezpz' })
   })
 
   test('/redirect-middleware', async () => {

test/fixtures/basic/pages/error2.vue

@@ -5,7 +5,7 @@
 <script>
 export default {
   asyncData({ error }) {
-    error({ message: 'Custom error' })
+    error({ message: 'Custom error', customProp: 'ezpz' })
   }
 }
 </script>

test/unit/basic.ssr.test.js

@@ -235,6 +235,7 @@ describe('basic ssr', () => {
     expect(html).toContain('Custom error')
     expect(error.message).toContain('Custom error')
     expect(error.statusCode).toBe(500)
+    expect(error.customProp).toBe('ezpz')
   })
 
   test('/error2 status code', async () => {