Fix noSelf in object literal methods (#1088)

GlassBricks · web-flow · commit a738dfc864b6 · 2021-08-15T21:25:42.000+02:00
* Fix noSelf in object literal methods

* Add isObjectLiteralExpression check on parent

This check is absent in the internal typescript method

* Add more tests for PR

Co-authored-by: Benjamin Ye &lt;24237065+enjoydambience@users.noreply.github.com&gt;
diff --git a/src/transformation/utils/function-context.ts b/src/transformation/utils/function-context.ts
@@ -113,17 +113,25 @@ function getSignatureDeclarations(
 ): ts.SignatureDeclaration[] {
     return signatures.flatMap(signature => {
         const signatureDeclaration = signature.getDeclaration();
+        let inferredType: ts.Type | undefined;
         if (
+            ts.isMethodDeclaration(signatureDeclaration) &&
+            ts.isObjectLiteralExpression(signatureDeclaration.parent) &&
+            !getExplicitThisParameter(signatureDeclaration)
+        ) {
+            inferredType = context.checker.getContextualTypeForObjectLiteralElement(signatureDeclaration);
+        } else if (
             (ts.isFunctionExpression(signatureDeclaration) || ts.isArrowFunction(signatureDeclaration)) &&
             !getExplicitThisParameter(signatureDeclaration)
         ) {
             // Infer type of function expressions/arrow functions
-            const inferredType = inferAssignedType(context, signatureDeclaration);
-            if (inferredType) {
-                const inferredSignatures = getAllCallSignatures(inferredType);
-                if (inferredSignatures.length > 0) {
-                    return inferredSignatures.map(s => s.getDeclaration());
-                }
+            inferredType = inferAssignedType(context, signatureDeclaration);
+        }
+
+        if (inferredType) {
+            const inferredSignatures = getAllCallSignatures(inferredType);
+            if (inferredSignatures.length > 0) {
+                return inferredSignatures.map(s => s.getDeclaration());
             }
         }
 
diff --git a/src/typescript-internal.d.ts b/src/typescript-internal.d.ts
@@ -26,5 +26,6 @@ declare module "typescript" {
 
     interface TypeChecker {
         getElementTypeOfArrayType(type: Type): Type | undefined;
+        getContextualTypeForObjectLiteralElement(element: ObjectLiteralElementLike): Type | undefined;
     }
 }
diff --git a/test/unit/objectLiteral.spec.ts b/test/unit/objectLiteral.spec.ts
@@ -63,3 +63,66 @@ test.each(['{x: "foobar"}.x', '{x: "foobar"}["x"]', '{x: () => "foobar"}.x()', '
         util.testExpression(expression).expectToMatchJsResult();
     }
 );
+
+describe("noSelf in functions", () => {
+    test("Explicit this: void parameter", () => {
+        // language=TypeScript
+        util.testFunction`
+            const obj: Record<string, (this: void, arg: string) => string> = {
+                method(a) {
+                    return a;
+                },
+                func: function(a) {
+                    return a;
+                },
+                arrow: (a) => {
+                    return a;
+                }
+            };
+            return [obj.method("a") ?? "nil", obj.func("b") ?? "nil", obj.arrow("c") ?? "nil"];
+        `.expectToMatchJsResult();
+    });
+
+    test("No self annotation", () => {
+        // language=TypeScript
+        util.testFunction`
+            const obj: Record<string, /** @noSelf */(arg: string) => string> = {
+                method(a) {
+                    return a;
+                },
+                func: function(a) {
+                    return a;
+                },
+                arrow: (a) => {
+                    return a;
+                }
+            };
+            return [obj.method("a") ?? "nil", obj.func("b") ?? "nil", obj.arrow("c") ?? "nil"];
+        `.expectToMatchJsResult();
+    });
+
+    test("individual function types", () => {
+        // language=TypeScript
+        util.testFunction`
+            interface FunctionContainer {
+                method: (this: void, a: string) => string
+                func: (this: void, a: string) => string
+                arrow: (this: void, a: string) => string
+            }
+
+            const obj: FunctionContainer = {
+                method(a) {
+                    return a
+                },
+                func: function(a) {
+                    return a
+                },
+                arrow: (a) => {
+                    return a
+                }
+            }
+
+            return [obj.method("a") ?? "nil", obj.func("b") ?? "nil", obj.arrow("c") ?? "nil"];
+        `.expectToMatchJsResult();
+    });
+});

Original file line number	Diff line number	Diff line change
`@@ -26,5 +26,6 @@ declare module "typescript" {`
`26`	`26`
`27`	`27`	`interface TypeChecker {`
`28`	`28`	`getElementTypeOfArrayType(type: Type): Type \| undefined;`
	`29`	`+ getContextualTypeForObjectLiteralElement(element: ObjectLiteralElementLike): Type \| undefined;`
`29`	`30`	`}`
`30`	`31`	`}`