Merge pull request microsoft#3477 from tinganho/customTypeGuardFormating

Fixes type predicate formatting

Author: mhegazy

src/services/formatting/formattingScanner.ts

@@ -224,7 +224,7 @@ module ts.formatting {
         }
 
         function isOnToken(): boolean {
-            let current = (lastTokenInfo && lastTokenInfo.token.kind) ||  scanner.getToken();
+            let current = (lastTokenInfo && lastTokenInfo.token.kind) || scanner.getToken();
             let startPos = (lastTokenInfo && lastTokenInfo.token.pos) || scanner.getStartPos();
             return startPos < endPos && current !== SyntaxKind.EndOfFileToken && !isTrivia(current);
         }

src/services/formatting/rules.ts

@@ -193,7 +193,7 @@ module ts.formatting {
         // Insert space after function keyword for anonymous functions
         public SpaceAfterAnonymousFunctionKeyword: Rule;
         public NoSpaceAfterAnonymousFunctionKeyword: Rule;
-        
+
         // Insert space after @ in decorator
         public SpaceBeforeAt: Rule;
         public NoSpaceAfterAt: Rule;
@@ -470,8 +470,9 @@ module ts.formatting {
             switch (context.contextNode.kind) {
                 case SyntaxKind.BinaryExpression:
                 case SyntaxKind.ConditionalExpression:
+                case SyntaxKind.TypePredicate:
                     return true;
-                
+
                 // equals in binding elements: function foo([[x, y] = [1, 2]])
                 case SyntaxKind.BindingElement:
                 // equals in type X = ...

src/services/formatting/tokenRange.ts

@@ -112,7 +112,7 @@ module ts.formatting {
             static AnyIncludingMultilineComments = TokenRange.FromTokens(TokenRange.Any.GetTokens().concat([SyntaxKind.MultiLineCommentTrivia]));
             static Keywords = TokenRange.FromRange(SyntaxKind.FirstKeyword, SyntaxKind.LastKeyword);
             static BinaryOperators = TokenRange.FromRange(SyntaxKind.FirstBinaryOperator, SyntaxKind.LastBinaryOperator);
-            static BinaryKeywordOperators = TokenRange.FromTokens([SyntaxKind.InKeyword, SyntaxKind.InstanceOfKeyword, SyntaxKind.OfKeyword]);
+            static BinaryKeywordOperators = TokenRange.FromTokens([SyntaxKind.InKeyword, SyntaxKind.InstanceOfKeyword, SyntaxKind.OfKeyword, SyntaxKind.IsKeyword]);
             static UnaryPrefixOperators = TokenRange.FromTokens([SyntaxKind.PlusPlusToken, SyntaxKind.MinusMinusToken, SyntaxKind.TildeToken, SyntaxKind.ExclamationToken]);
             static UnaryPrefixExpressions = TokenRange.FromTokens([SyntaxKind.NumericLiteral, SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.OpenBracketToken, SyntaxKind.OpenBraceToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword]);
             static UnaryPreincrementExpressions = TokenRange.FromTokens([SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword]);

tests/cases/fourslash/functionTypePredicateFormatting.ts

@@ -0,0 +1,7 @@
+/// <reference path='fourslash.ts' />
+
+//// /**/function bar(a: A):     a        is       B    {}
+
+goTo.marker();
+format.document();
+verify.currentLineContentIs("function bar(a: A): a is B { }");