Pass entire text through formatWithShebang() to format() (#1718)

* Verify shebang tests against Babylon as well as Flow/Typescript

* Pass entire text through formatWithShebang() to format()

That way, we won't have to do any arithmetic on range and cursor
locations when there is a shebang. See here for details:

https://github.com/prettier/prettier/pull/1637#issuecomment-303846507

This required changing comment printing such that comments that are
actually shebangs are just ignored.

* Add curly brace after `if`

See https://github.com/prettier/prettier/pull/1718#discussion_r118382574

index.js

@@ -235,11 +235,10 @@ function formatWithShebang(text, opts) {
 
   const index = text.indexOf("\n");
   const shebang = text.slice(0, index + 1);
-  const programText = text.slice(index + 1);
   const nextChar = text.charAt(index + 1);
   const newLine = nextChar === "\n" ? "\n" : nextChar === "\r" ? "\r\n" : "";
 
-  return shebang + newLine + format(programText, opts);
+  return shebang + newLine + format(text, opts);
 }
 
 module.exports = {

src/comments.js

@@ -791,7 +791,7 @@ function handleVariableDeclaratorComments(
   return false;
 }
 
-function printComment(commentPath) {
+function printComment(commentPath, options) {
   const comment = commentPath.getValue();
   comment.printed = true;
 
@@ -801,6 +801,10 @@ function printComment(commentPath) {
       return "/*" + comment.value + "*/";
     case "CommentLine":
     case "Line":
+      // Don't print the shebang, it's taken care of in index.js
+      if (options.originalText.slice(util.locStart(comment)).startsWith("#!")) {
+        return "";
+      }
       return "//" + comment.value;
     default:
       throw new Error("Not a comment: " + JSON.stringify(comment));
@@ -832,7 +836,10 @@ function getQuasiRange(expr) {
 
 function printLeadingComment(commentPath, print, options) {
   const comment = commentPath.getValue();
-  const contents = printComment(commentPath);
+  const contents = printComment(commentPath, options);
+  if (!contents) {
+    return "";
+  }
   const isBlock = util.isBlockComment(comment);
 
   // Leading block comments should see if they need to stay on the
@@ -849,7 +856,10 @@ function printLeadingComment(commentPath, print, options) {
 
 function printTrailingComment(commentPath, print, options) {
   const comment = commentPath.getValue();
-  const contents = printComment(commentPath);
+  const contents = printComment(commentPath, options);
+  if (!contents) {
+    return "";
+  }
   const isBlock = util.isBlockComment(comment);
 
   if (
@@ -895,8 +905,8 @@ function printDanglingComments(path, options, sameIndent) {
 
   path.each(commentPath => {
     const comment = commentPath.getValue();
-    if (!comment.leading && !comment.trailing) {
-      parts.push(printComment(commentPath));
+    if (comment && !comment.leading && !comment.trailing) {
+      parts.push(printComment(commentPath, options));
     }
   }, "comments");
 
@@ -930,7 +940,11 @@ function printComments(path, print, options, needsSemi) {
     const trailing = types.getFieldValue(comment, "trailing");
 
     if (leading) {
-      leadingParts.push(printLeadingComment(commentPath, print, options));
+      const contents = printLeadingComment(commentPath, print, options);
+      if (!contents) {
+        return;
+      }
+      leadingParts.push(contents);
 
       const text = options.originalText;
       if (util.hasNewline(text, util.skipNewline(text, util.locEnd(comment)))) {

tests/shebang/jsfmt.spec.js

@@ -1 +1 @@
-run_spec(__dirname, null, ["typescript"]);
+run_spec(__dirname, null, ["typescript", "babylon"]);