Fix #1633 – feat(array wrapper): return ErrorWrapper when index not found with .at()

docs/api/wrapper-array/at.md

@@ -2,6 +2,7 @@
 
 Returns `Wrapper` at `index` passed. Uses zero based numbering (i.e. first item is at index 0).
 If `index` is negative, indexing starts from the last element (i.e. last item is at index -1).
+When none is found, returns an `ErrorWrapper`.
 
 - **Arguments:**
 
@@ -23,4 +24,7 @@ expect(secondDiv.is('div')).toBe(true)
 
 const lastDiv = divArray.at(-1)
 expect(lastDiv.is('div')).toBe(true)
+
+const nonExistentDiv = divArray.at(1000)
+expect(nonExistentDiv.exists()).toBe(false)
 ```

packages/test-utils/src/wrapper-array.js

@@ -3,6 +3,7 @@
 import type Wrapper from './wrapper'
 import type VueWrapper from './vue-wrapper'
 import { throwError } from 'shared/util'
+import ErrorWrapper from './error-wrapper'
 
 export default class WrapperArray implements BaseWrapper {
   +wrappers: Array<Wrapper | VueWrapper>
@@ -23,14 +24,9 @@ export default class WrapperArray implements BaseWrapper {
     })
   }
 
-  at(index: number): Wrapper | VueWrapper {
+  at(index: number): Wrapper | VueWrapper | ErrorWrapper {
     const normalizedIndex = index < 0 ? this.length + index : index
-    if (normalizedIndex > this.length - 1 || normalizedIndex < 0) {
-      let error = `no item exists at ${index}`
-      error += index < 0 ? ` (normalized to ${normalizedIndex})` : ''
-      throwError(error)
-    }
-    return this.wrappers[normalizedIndex]
+    return this.wrappers[normalizedIndex] || new ErrorWrapper('')
   }
 
   attributes(): void {

test/specs/wrapper-array/at.spec.js

@@ -26,33 +26,12 @@ describeWithShallowAndMount('at', mountingMethod => {
     expect(first.classes()).to.contain('index-first')
   })
 
-  it('throws error if no item exists at index', () => {
-    const index = 2
+  it('returns ErrorWrapper at index when not found', () => {
     const TestComponent = {
-      template: '<div><p /><p class="index-1"/></div>'
+      template: '<div></div>'
     }
-    const message = `[vue-test-utils]: no item exists at ${index}`
-    expect(() =>
-      mountingMethod(TestComponent)
-        .findAll('p')
-        .at(index)
-    )
-      .to.throw()
-      .with.property('message', message)
-  })
-
-  it('throws error if no item exists at negative index', () => {
-    const index = -3
-    const TestComponent = {
-      template: '<div><p /><p class="index-1"/></div>'
-    }
-    const message = `[vue-test-utils]: no item exists at -3 (normalized to -1)`
-    expect(() =>
-      mountingMethod(TestComponent)
-        .findAll('p')
-        .at(index)
-    )
-      .to.throw()
-      .with.property('message', message)
+    const all = mountingMethod(TestComponent).findAll('p')
+    const nonExistent = all.at(0)
+    expect(nonExistent.exists()).to.equal(false)
   })
 })