Add | undefined to all optional properties too

in declarationEmitter.ts

Author: sandersn

src/compiler/declarationEmitter.ts

@@ -1593,9 +1593,11 @@ namespace ts {
                 emitTypeOfVariableDeclarationFromTypeLiteral(node);
             }
             else if (!hasModifier(node.parent, ModifierFlags.Private)) {
-                // use the checker's type, not the declared type, for an initialized parameter (that isn't a parameter property)
-                const isInitializedParameter = node.initializer && !(getModifierFlags(node) & ModifierFlags.ParameterPropertyModifier);
-                const typeNode = isInitializedParameter ? undefined : node.type;
+                // use the checker's type, not the declared type,
+                // for optional parameters and initialized ones that aren't a parameter property
+                const typeShouldAddUndefined = resolver.isOptionalParameter(node) ||
+                    node.initializer && !(getModifierFlags(node) & ModifierFlags.ParameterPropertyModifier);
+                const typeNode = typeShouldAddUndefined ? undefined : node.type;
                 writeTypeOfDeclaration(node, typeNode, getParameterDeclarationTypeVisibilityError);
             }
 

tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.js

@@ -88,7 +88,7 @@ function removeNothing(y) {
 
 
 //// [defaultParameterAddsUndefinedWithStrictNullChecks.d.ts]
-declare function f(addUndefined1?: string | undefined, addUndefined2?: number): number;
+declare function f(addUndefined1?: string | undefined, addUndefined2?: number | undefined): number;
 declare function g(addUndefined: string | undefined, addDefined: number): number;
 declare let total: number;
 declare function foo1(x: string | undefined, b: number): void;

tests/baselines/reference/destructureOptionalParameter.js

@@ -36,7 +36,7 @@ function f2(_a) {
 declare function f1({a, b}?: {
     a: number;
     b: string;
-}): void;
+} | undefined): void;
 declare function f2({a, b}?: {
     a: number;
     b: number;
@@ -49,11 +49,11 @@ interface QueryMetadata {
 }
 interface QueryMetadataFactory {
     (selector: Type | string, {descendants, read}?: {
-        descendants?: boolean;
+        descendants?: boolean | undefined;
         read?: any;
-    }): ParameterDecorator;
+    } | undefined): ParameterDecorator;
     new (selector: Type | string, {descendants, read}?: {
-        descendants?: boolean;
+        descendants?: boolean | undefined;
         read?: any;
-    }): QueryMetadata;
+    } | undefined): QueryMetadata;
 }

tests/baselines/reference/optionalMethods.js

@@ -132,7 +132,7 @@ declare class Bar {
     a: number;
     b?: number;
     c?: number | undefined;
-    constructor(d?: number, e?: number);
+    constructor(d?: number | undefined, e?: number);
     f(): number;
     g?(): number;
     h?(): number;