feat: add generic for wrapper.find() and wrapper.get() (vuejs#1871)

* feat: add generic for wrapper.find() and wrapper.get()

* refactor: change HTMLElement -> Element

* fix: fix the tests for wrapper

* fix: forgot to apply the generic

* test: added the simple test

Author: standbyoneself

packages/test-utils/types/index.d.ts

@@ -75,15 +75,15 @@ interface BaseWrapper {
   selector: Selector | void
 }
 
-export interface Wrapper<V extends Vue | null> extends BaseWrapper {
+export interface Wrapper<V extends Vue | null, el extends Element = Element> extends BaseWrapper {
   readonly vm: V
-  readonly element: HTMLElement
+  readonly element: el
   readonly options: WrapperOptions
 
   get<R extends Vue> (selector: VueClass<R>): Wrapper<R>
   get<R extends Vue> (selector: ComponentOptions<R>): Wrapper<R>
   get<Props = DefaultProps, PropDefs = PropsDefinition<Props>>(selector: FunctionalComponentOptions<Props, PropDefs>): Wrapper<Vue>
-  get (selector: string): Wrapper<Vue>
+  get<el extends Element>(selector: string): Wrapper<Vue, el>
   get (selector: RefSelector): Wrapper<Vue>
   get (selector: NameSelector): Wrapper<Vue>
 
@@ -96,7 +96,7 @@ export interface Wrapper<V extends Vue | null> extends BaseWrapper {
   find<R extends Vue> (selector: VueClass<R>): Wrapper<R>
   find<R extends Vue> (selector: ComponentOptions<R>): Wrapper<R>
   find<Props = DefaultProps, PropDefs = PropsDefinition<Props>>(selector: FunctionalComponentOptions<Props, PropDefs>): Wrapper<Vue>
-  find (selector: string): Wrapper<Vue>
+  find<el extends Element>(selector: string): Wrapper<Vue, el>
   find (selector: RefSelector): Wrapper<Vue>
   find (selector: NameSelector): Wrapper<Vue>
 

packages/test-utils/types/test/wrapper.ts

@@ -51,7 +51,7 @@ wrapper.findComponent(ClassComponent)
 wrapper.vm.foo
 wrapper.vm.$emit('event', 'arg')
 
-let el: HTMLElement = wrapper.element
+let el: Element = wrapper.element
 
 let selector: Selector | void
 
@@ -68,6 +68,8 @@ selector = found.selector
 found = wrapper.find({ name: 'my-button' })
 selector = found.selector
 
+wrapper.find<HTMLInputElement>('input').element.value
+
 let array = wrapper.findAll('.bar')
 selector = array.selector
 array = wrapper.findAll(normalOptions)