Return {formatted, cursor} from printDocToString() instead of mutating options

josephfrazier · josephfrazier · commit 1fa6b4e0ae24 · 2017-06-01T18:40:18.000-04:00
See #1637 (comment)
diff --git a/index.js b/index.js
@@ -76,7 +76,9 @@ function formatWithCursor(text, opts, addAlignmentSize) {
   const astComments = attachComments(text, ast, opts);
   const doc = printAstToDoc(ast, opts, addAlignmentSize);
   opts.newLine = guessLineEnding(text);
-  const str = printDocToString(doc, opts);
+  const toStringResult = printDocToString(doc, opts);
+  const str = toStringResult.formatted;
+  const cursorOffsetResult = toStringResult.cursor;
   ensureAllCommentsPrinted(astComments);
   // Remove extra leading indentation as well as the added indentation after last newline
   if (addAlignmentSize > 0) {
@@ -86,7 +88,7 @@ function formatWithCursor(text, opts, addAlignmentSize) {
   if (cursorOffset !== undefined) {
     return {
       formatted: str,
-      cursorOffset: opts.cursorOffsetResult + cursorOffset
+      cursorOffset: cursorOffsetResult + cursorOffset
     };
   }
 
diff --git a/src/doc-printer.js b/src/doc-printer.js
@@ -420,13 +420,15 @@ function printDocToString(doc, options) {
   const cursorPlaceholderIndex = out.indexOf(cursor.placeholder);
   if (cursorPlaceholderIndex !== -1) {
     const beforeCursor = out.slice(0, cursorPlaceholderIndex).join("");
-    options.cursorOffsetResult = beforeCursor.length;
     const afterCursor = out.slice(cursorPlaceholderIndex + 1).join("");
 
-    return beforeCursor + afterCursor;
+    return {
+      formatted: beforeCursor + afterCursor,
+      cursor: beforeCursor.length
+    };
   }
 
-  return out.join("");
+  return { formatted: out.join("") };
 }
 
 module.exports = { printDocToString };
