JS: Format if statements with no else on a single line

lib/src/js/printer.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of js_ast;
 
 
 class JavaScriptPrintingOptions {
   final bool shouldCompressOutput;
   final bool minifyLocalVariables;
@@ skipping 163 matching lines @@
     if (shouldCompressOutput) {
       pendingSemicolon = true;
     } else {
       out(";");
       forceLine();
     }
   }
 
   void outIndent(String str) { indent(); out(str); }
   void outIndentLn(String str) { indent(); outLn(str); }
+
+  bool _skipNextIndent = false;

[Jennifer Messerly, 2015/12/15 23:57:10]

style nit: it looks like they're keeping all fields up top.

[ochafik, 2015/12/16 02:00:37]

Done.

+  void skipNextIndent() {
+    _skipNextIndent = true;
+  }
   void indent() {
+    if (_skipNextIndent) {
+      _skipNextIndent = false;
+      return;
+    }
     if (!shouldCompressOutput) {
       out(indentation);
     }
   }
 
   visit(Node node) {
     context.enterNode(node);
     node.accept(this);
     context.exitNode(node);
   }
@@ skipping 97 matching lines @@
         then = new Block(<Statement>[then]);
       }
     }
     if (shouldIndent) indent();
     out("if");
     spaceOut();
     out("(");
     visitNestedExpression(node.condition, EXPRESSION,
                           newInForInit: false, newAtStatementBegin: false);
     out(")");
-    bool thenWasBlock =
-        blockBody(then, needsSeparation: false, needsNewline: !hasElse);
+    bool thenWasBlock;

[Jennifer Messerly, 2015/12/15 23:57:10]

nice readability improvement.

Would it be possible to put this under a flag?

See JavaScriptPrintingOptions at the top of the file.

We can set this flag always in DDC. But this allows us to upstream the changes
to dart2js.

[ochafik, 2015/12/16 02:00:37]

Done (didn't realize the contamination potential :-))

+    if (!hasElse && then is! Block) {
+      thenWasBlock = false;
+      if (!shouldCompressOutput) spaceOut();

[Jennifer Messerly, 2015/12/15 23:57:10]

spaceOut() already does the shouldCompressOutput, so this can just be:

    spaceOut();

[ochafik, 2015/12/16 02:00:37]

D'oh!

+      skipNextIndent();
+      visit(then);
+    } else {
+      thenWasBlock = blockBody(then, needsSeparation: false, needsNewline: !hasElse);

[Jennifer Messerly, 2015/12/15 23:57:10]

long line

[ochafik, 2015/12/16 02:00:37]

Done.

+    }
     if (hasElse) {
       if (thenWasBlock) {
         spaceOut();
       } else {
         indent();
       }
       out("else");
       if (elsePart is If) {
         pendingSpace = true;
         ifOut(elsePart, false);
@@ skipping 1294 matching lines @@
     declare(node.name);
     node.function.accept(this);
   }
 
   visitClassExpression(ClassExpression node) {
     declare(node.name);
     if (node.heritage != null) node.heritage.accept(this);
     for (Method element in node.methods) element.accept(this);
   }
 }