build(deps): upgrade to TypeScript 4

packages/compiler-sfc/src/parse.ts

@@ -176,7 +176,7 @@ export function parse(
             `its syntax will be ambiguous outside of the component.`
         )
       )
-      delete descriptor.scriptSetup
+      descriptor.scriptSetup = null
     }
     if (descriptor.script && descriptor.script.src) {
       errors.push(
@@ -185,7 +185,7 @@ export function parse(
             `also present because they must be processed together.`
         )
       )
-      delete descriptor.script
+      descriptor.script = null
     }
   }
 

packages/reactivity/__tests__/effect.spec.ts

@@ -66,6 +66,7 @@ describe('reactivity/effect', () => {
     effect(() => (dummy = obj.prop))
 
     expect(dummy).toBe('value')
+    // @ts-ignore
     delete obj.prop
     expect(dummy).toBe(undefined)
   })
@@ -76,6 +77,7 @@ describe('reactivity/effect', () => {
     effect(() => (dummy = 'prop' in obj))
 
     expect(dummy).toBe(true)
+    // @ts-ignore
     delete obj.prop
     expect(dummy).toBe(false)
     obj.prop = 12
@@ -90,6 +92,7 @@ describe('reactivity/effect', () => {
     effect(() => (dummy = counter.num))
 
     expect(dummy).toBe(0)
+    // @ts-ignore
     delete counter.num
     expect(dummy).toBe(2)
     parentCounter.num = 4
@@ -106,8 +109,10 @@ describe('reactivity/effect', () => {
     effect(() => (dummy = 'num' in counter))
 
     expect(dummy).toBe(true)
+    // @ts-ignore
     delete counter.num
     expect(dummy).toBe(true)
+    // @ts-ignore
     delete parentCounter.num
     expect(dummy).toBe(false)
     counter.num = 3
@@ -219,6 +224,7 @@ describe('reactivity/effect', () => {
     expect(hasDummy).toBe(true)
     obj[key] = 'newValue'
     expect(dummy).toBe('newValue')
+    // @ts-ignore
     delete obj[key]
     expect(dummy).toBe(undefined)
     expect(hasDummy).toBe(false)
@@ -648,6 +654,7 @@ describe('reactivity/effect', () => {
       newValue: 2
     })
 
+    // @ts-ignore
     delete obj.foo
     expect(dummy).toBeUndefined()
     expect(onTrigger).toHaveBeenCalledTimes(2)

packages/reactivity/__tests__/readonly.spec.ts

@@ -68,18 +68,21 @@ describe('reactivity/readonly', () => {
         `Set operation on key "Symbol(qux)" failed: target is readonly.`
       ).toHaveBeenWarnedLast()
 
+      // @ts-ignore
       delete wrapped.foo
       expect(wrapped.foo).toBe(1)
       expect(
         `Delete operation on key "foo" failed: target is readonly.`
       ).toHaveBeenWarnedLast()
 
+      // @ts-ignore
       delete wrapped.bar.baz
       expect(wrapped.bar.baz).toBe(2)
       expect(
         `Delete operation on key "baz" failed: target is readonly.`
       ).toHaveBeenWarnedLast()
 
+      // @ts-ignore
       delete wrapped[qux]
       expect(wrapped[qux]).toBe(3)
       expect(

packages/runtime-core/__tests__/apiLifecycle.spec.ts

@@ -356,6 +356,7 @@ describe('api: lifecycle hooks', () => {
       newValue: 2
     })
 
+    // @ts-ignore
     delete obj.bar
     await nextTick()
     expect(onTrigger).toHaveBeenCalledTimes(2)

packages/runtime-core/__tests__/apiWatch.spec.ts

@@ -707,6 +707,7 @@ describe('api: watch', () => {
       newValue: 2
     })
 
+    // @ts-ignore
     delete obj.foo
     await nextTick()
     expect(dummy).toBeUndefined()

packages/runtime-core/src/apiCreateApp.ts

@@ -258,7 +258,7 @@ export function createAppAPI<HostElement>(
       },
 
       provide(key, value) {
-        if (__DEV__ && key in context.provides) {
+        if (__DEV__ && (key as string | symbol) in context.provides) {
           warn(
             `App already provides property with key "${String(key)}". ` +
               `It will be overwritten with the new value.`

packages/runtime-core/src/apiInject.ts

@@ -37,7 +37,7 @@ export function inject(
   const instance = currentInstance || currentRenderingInstance
   if (instance) {
     const provides = instance.provides
-    if (key in provides) {
+    if ((key as string | symbol) in provides) {
       // TS doesn't allow symbol as index type
       return provides[key as string]
     } else if (arguments.length > 1) {