fix: preserve calc when extra parentheses are used (#187)

* fix: preserve calc when extra parentheses are used

* fix: ensure extra parentheses are removed

Author: tannerdolby

src/lib/stringifier.js

@@ -73,12 +73,17 @@ module.exports = function (calc, node, originalValue, options, result, item) {
   let str = stringify(node, options.precision);
 
   const shouldPrintCalc =
-    node.type === 'MathExpression' || node.type === 'Function';
+    node.type === 'MathExpression' || node.type === 'Function' ||
+    node.type === 'ParenthesizedExpression';
 
   if (shouldPrintCalc) {
     // if calc expression couldn't be resolved to a single value, re-wrap it as
     // a calc()
-    str = `${calc}(${str})`;
+    if (node.type === 'ParenthesizedExpression') {
+      str = `${calc}${str}`;
+    } else {
+      str = `${calc}(${str})`;
+    }
 
     // if the warnWhenCannotResolve option is on, inform the user that the calc
     // expression could not be resolved to a single value

test/index.js

@@ -768,6 +768,14 @@ test(
   )
 );
 
+test(
+  'should preserve calc when extra parentheses are used',
+  testValue(
+    'calc((var(--circumference) / var(--number-of-segments)))',
+    'calc(var(--circumference)/var(--number-of-segments))'
+  )
+);
+
 test('precision for calc', testValue('calc(100% / 3 * 3)', '100%'));
 
 test(