optimize and add more tests for parenthesized case

src/services/refactors/convertStringOrTemplateLiteral.ts

@@ -33,7 +33,16 @@ namespace ts.refactor.convertStringOrTemplateLiteral {
 
     function getNodeOrParentOfParentheses(file: SourceFile, startPosition: number) {
         const node = getTokenAtPosition(file, startPosition);
-        if (isParenthesizedExpression(node.parent) && isBinaryExpression(node.parent.parent)) return node.parent.parent;
+        const nestedBinary = getParentBinaryExpression(node);
+        const isNonStringBinary = !isStringConcatenationValid(nestedBinary);
+
+        if (
+            isNonStringBinary &&
+            isParenthesizedExpression(nestedBinary.parent) &&
+            isBinaryExpression(nestedBinary.parent.parent)
+        ) {
+            return nestedBinary.parent.parent;
+        }
         return node;
     }
 

tests/cases/fourslash/refactorConvertStringOrTemplateLiteral_ToTemplateParenthFromExpr.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// const foo = "foobar is " + (/*x*/42/*y*/ + 6) + " years old"
+
+goTo.select("x", "y");
+edit.applyRefactor({
+    refactorName: "Convert string concatenation or template literal",
+    actionName: "Convert to template literal",
+    actionDescription: "Convert to template literal",
+    newContent:
+`const foo = \`foobar is \${42 + 6} years old\``,
+});
+

tests/cases/fourslash/refactorConvertStringOrTemplateLiteral_ToTemplateParenthFromStr.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// const foo = "foobar is " + (/*x*/42/*y*/ + 6 + "str") + " years old"
+
+goTo.select("x", "y");
+edit.applyRefactor({
+    refactorName: "Convert string concatenation or template literal",
+    actionName: "Convert to template literal",
+    actionDescription: "Convert to template literal",
+    newContent:
+`const foo = "foobar is " + (\`\${42 + 6}str\`) + " years old"`,
+});
+