feat(types): update to Typescript 3.9 (#1106)

test-dts/functionalComponent.test-d.tsx

@@ -1,13 +1,15 @@
-import { expectError, expectType } from 'tsd'
-import { FunctionalComponent } from './index'
+import { FunctionalComponent, expectError, expectType } from './index'
 
 // simple function signature
 const Foo = (props: { foo: number }) => props.foo
 
 // TSX
 expectType<JSX.Element>(<Foo foo={1} />)
-// expectError(<Foo />) // tsd does not catch missing type errors
+// @ts-expect-error
+expectError(<Foo />)
+//  @ts-expect-error
 expectError(<Foo foo="bar" />)
+//  @ts-expect-error
 expectError(<Foo baz="bar" />)
 
 // Explicit signature with props + emits
@@ -18,8 +20,11 @@ const Bar: FunctionalComponent<
   expectType<number>(props.foo)
 
   emit('update', 123)
+  //  @ts-expect-error
   expectError(emit('nope'))
+  //  @ts-expect-error
   expectError(emit('update'))
+  //  @ts-expect-error
   expectError(emit('update', 'nope'))
 }
 
@@ -27,15 +32,20 @@ const Bar: FunctionalComponent<
 Bar.props = {
   foo: Number
 }
+//  @ts-expect-error
 expectError((Bar.props = { foo: String }))
 
 Bar.emits = {
   update: value => value > 1
 }
+//  @ts-expect-error
 expectError((Bar.emits = { baz: () => void 0 }))
 
 // TSX
 expectType<JSX.Element>(<Bar foo={1} />)
-// expectError(<Foo />) // tsd does not catch missing type errors
+//  @ts-expect-error
+expectError(<Foo />)
+//  @ts-expect-error
 expectError(<Bar foo="bar" />)
+//  @ts-expect-error
 expectError(<Foo baz="bar" />)