fix: return empty string for text() on comments

Fixes vuejs#342

Author: cexbrayat

src/domWrapper.ts

@@ -4,6 +4,7 @@ import { createWrapperError } from './errorWrapper'
 import { TriggerOptions, createDOMEvent } from './createDomEvent'
 import { config } from './config'
 import { isElementVisible } from './utils/isElementVisible'
+import { textContent } from './utils'
 
 export class DOMWrapper<ElementType extends Element> {
   element: ElementType
@@ -45,7 +46,7 @@ export class DOMWrapper<ElementType extends Element> {
   }
 
   text() {
-    return this.element.textContent?.trim()
+    return textContent(this.element)
   }
 
   html() {

src/utils.ts

@@ -96,3 +96,11 @@ export function isHTML(str: string) {
 
   return false
 }
+
+export function textContent(element: Element): string {
+  // we check if the element is a comment first
+  // to return an empty string in that case, instead of the comment content
+  return element.nodeType !== Node.COMMENT_NODE
+    ? element.textContent?.trim()
+    : ''
+}

src/vueWrapper.ts

@@ -7,7 +7,7 @@ import { FindAllComponentsSelector, FindComponentSelector } from './types'
 import { createWrapperError } from './errorWrapper'
 import { TriggerOptions } from './createDomEvent'
 import { find, matches } from './utils/find'
-import { mergeDeep } from './utils'
+import { mergeDeep, textContent } from './utils'
 import { emitted } from './emit'
 
 export class VueWrapper<T extends ComponentPublicInstance> {
@@ -86,7 +86,7 @@ export class VueWrapper<T extends ComponentPublicInstance> {
   }
 
   text() {
-    return this.element.textContent?.trim()
+    return textContent(this.element)
   }
 
   find<K extends keyof HTMLElementTagNameMap>(

tests/text.spec.ts

@@ -26,4 +26,17 @@ describe('text', () => {
 
     expect(wrapper.text()).toBe('foobarbaz')
   })
+
+  it('returns empty string when the root element is a comment', () => {
+    const Component = defineComponent({
+      template: '<div v-if="condition">Hello</div>',
+      setup() {
+        return { condition: false }
+      }
+    })
+
+    const wrapper = mount(Component)
+
+    expect(wrapper.text()).toBe('')
+  })
 })