feature(type): treat keyof this as any so that it does not work i…

…n a strange unexpected way. ref #430
deepkit · Apr 12, 2023 · e02fa0d · e02fa0d
1 parent ece8c02
commit e02fa0d
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diff --git a/packages/type-compiler/src/compiler.ts b/packages/type-compiler/src/compiler.ts
@@ -1640,6 +1640,13 @@ export class ReflectionTransformer implements CustomTransformer {
                 //TypeScript does not narrow types down
                 const narrowed = node as TypeOperatorNode;
 
+                if (narrowed.type.kind === SyntaxKind.ThisType) {
+                    //for the moment we treat `keyof this` as any, since `this` is not implemented at all.
+                    //this makes it possible that the code above works at least.
+                    program.pushOp(ReflectionOp.any);
+                    break;
+                }
+
                 switch (narrowed.operator) {
                     case SyntaxKind.KeyOfKeyword: {
                         this.extractPackStructOfType(narrowed.type, program);

diff --git a/packages/type-compiler/tests/transpile.spec.ts b/packages/type-compiler/tests/transpile.spec.ts
@@ -426,3 +426,14 @@ test('extends with reference to this', () => {
     //currently broken as it returns LogEntityForSchema.options.entity, probably a bug in TS
     // expect(res.app).toContain(`() => this.options.entity,`);
 });
+
+test('keyof this expression', () => {
+    const res = transpile({
+        'app': `
+        class Factory {
+            someFunctionC(input: keyof this) { }
+        }
+        `
+    });
+    console.log(res);
+});
diff --git a/packages/type/tests/type.spec.ts b/packages/type/tests/type.spec.ts
@@ -1453,3 +1453,23 @@ test('issue-429: invalid function detection', () => {
     expect(stringifyResolvedType(typeOf<isFunction>())).toBe('false');
     expect(stringifyResolvedType(typeOf<keys>())).toBe(`'someFunction'`);
 });
+
+test('issue-430: referring to this', () => {
+    class SomeClass {
+        fieldA!: string;
+        fieldB!: number;
+        fieldC!: boolean;
+
+        someFunctionA() { }
+        someFunctionB(input: string) { }
+        someFunctionC(input: keyof this /* behaves the same with keyof anything */) { }
+    }
+
+    type ArrowFunction = (...args: any) => any;
+    type MethodKeys<T> = {[K in keyof T]: T[K] extends ArrowFunction ? K : never}[keyof T];
+    type keys = MethodKeys<SomeClass>;
+
+    //for the moment we treat `keyof this` as any, since `this` is not implemented at all.
+    //this makes it possible that the code above works at least.
+    expect(stringifyResolvedType(typeOf<keys>())).toBe(`'someFunctionA' | 'someFunctionB' | 'someFunctionC'`);
+});