chore: extracted isMethodType to ts-utils

Author: marekdedic

Diff for: packages/eslint-plugin-svelte/src/rules/require-event-prefix.ts

@@ -1,9 +1,8 @@
 import { createRule } from '../utils/index.js';
-import { type TSTools, getTypeScriptTools } from '../utils/ts-utils/index.js';
+import { type TSTools, getTypeScriptTools, isMethodType } from '../utils/ts-utils/index.js';
 import {
 	type MethodSignature,
 	type Symbol,
-	SymbolFlags,
 	SyntaxKind,
 	type Type,
 	type TypeReferenceNode,
@@ -57,7 +56,7 @@ export default createRule('require-event-prefix', {
 				}
 				for (const property of propsType.getProperties()) {
 					if (
-						isFunctionLike(property) &&
+						isFunctionLike(property, tsTools) &&
 						!property.getName().startsWith('on') &&
 						(checkAsyncFunctions || !isFunctionAsync(property))
 					) {
@@ -94,9 +93,12 @@ function getPropsType(node: CallExpression, tsTools: TSTools): Type | undefined
 	return tsTools.service.program.getTypeChecker().getTypeAtLocation(tsNode);
 }
 
-function isFunctionLike(functionSymbol: Symbol): boolean {
+function isFunctionLike(functionSymbol: Symbol, tsTools: TSTools): boolean {
 	return (
-		(functionSymbol.getFlags() & SymbolFlags.Method) !== 0 ||
+		isMethodType(
+			tsTools.service.program.getTypeChecker().getTypeOfSymbol(functionSymbol),
+			tsTools.ts
+		) ||
 		(functionSymbol.valueDeclaration?.kind === SyntaxKind.PropertySignature &&
 			(functionSymbol.valueDeclaration as PropertySignature).type?.kind === SyntaxKind.FunctionType)
 	);

Diff for: packages/eslint-plugin-svelte/src/utils/ts-utils/index.ts

@@ -190,6 +190,12 @@ export function isVoidType(type: TS.Type, ts: TypeScript): boolean {
 export function isNullType(type: TS.Type, ts: TypeScript): boolean {
 	return (type.flags & ts.TypeFlags.Null) !== 0;
 }
+/**
+ * Check whether the given type is a method type or not.
+ */
+export function isMethodType(type: TS.Type, ts: TypeScript): boolean {
+	return (type.flags & ts.SymbolFlags.Method) !== 0;
+}
 /**
  * Check whether the given type is a possibly falsy type or not.
  */