Modified the emitComment logic to handle emitting leading or trailing spaces depending on flags

Leading comments have trailing separator while trailing comments have leading space
This removes the extra trailing space in the trailing comments

Author: sheetalkamat

src/compiler/emitter.ts

@@ -167,14 +167,23 @@ module ts {
             });
         }
 
-        function emitComments(comments: Comment[], writer: EmitTextWriter, writeComment: (comment: Comment, writer: EmitTextWriter) => void) {
+        function emitComments(comments: Comment[], trailingSeparator: boolean, writer: EmitTextWriter, writeComment: (comment: Comment, writer: EmitTextWriter) => void) {
+            var emitLeadingSpace = !trailingSeparator;
             forEach(comments, comment => {
+                if (emitLeadingSpace) {
+                    writer.write(" ");
+                    emitLeadingSpace = false;
+                }
                 writeComment(comment, writer);
                 if (comment.hasTrailingNewLine) {
                     writer.writeLine();
-                } else {
+                } else if (trailingSeparator) {
                     writer.write(" ");
                 }
+                else {
+                    // Emit leading space to separate comment during next comment emit
+                    emitLeadingSpace = true;
+                }
             });
         }
 
@@ -1941,18 +1950,16 @@ module ts {
             function emitLeadingDeclarationComments(node: Declaration) {
                 var leadingComments = getLeadingComments(currentSourceFile.text, node.pos);
                 emitNewLineBeforeLeadingComments(node, leadingComments, writer);
-                emitComments(leadingComments, writer, writeComment);
+                // Leading comments are emitted at /*leading comment1 */space/*leading comment*/space
+                emitComments(leadingComments, /*trailingSeparator*/ true, writer, writeComment);
             }
 
             function emitTrailingDeclarationComments(node: Declaration) {
                 // Emit the trailing declaration comments only if the parent's end doesnt match
                 if (node.parent.kind === SyntaxKind.SourceFile || node.end !== node.parent.end) {
                     var trailingComments = getTrailingComments(currentSourceFile.text, node.end);
-                    if (trailingComments && trailingComments.length) {
-                        // Trailing comments are emitting on same line, so write a space between comment
-                        writer.write(" ");
-                    }
-                    emitComments(trailingComments, writer, writeComment);
+                    // trailing comments are emitted at space/*trailing comment1 */space/*trailing comment*/
+                    emitComments(trailingComments, /*trailingSeparator*/ false, writer, writeComment);
                 }
             }
 
@@ -2068,7 +2075,8 @@ module ts {
                 if (declaration) {
                     var jsDocComments = getJsDocComments(declaration, currentSourceFile);
                     emitNewLineBeforeLeadingComments(declaration, jsDocComments, writer);
-                    emitComments(jsDocComments, writer, writeCommentRange);
+                    // jsDoc comments are emitted at /*leading comment1 */space/*leading comment*/space
+                    emitComments(jsDocComments, /*trailingSeparator*/ true, writer, writeCommentRange);
                 }
             }
 

tests/baselines/reference/AmbientModuleAndNonAmbientClassWithSameNameAndCommonRoot.js

@@ -37,4 +37,4 @@ var A;
 //// [test.js]
 var p;
 var p = A.Point.Origin;
-var p = new A.Point(0, 0); // unexpected error here, bug 840000 
+var p = new A.Point(0, 0); // unexpected error here, bug 840000

tests/baselines/reference/ambiguousOverloadResolution.js

@@ -28,4 +28,4 @@ var B = (function (_super) {
     return B;
 })(A);
 var x;
-var t = f(x, x); // Not an error 
+var t = f(x, x); // Not an error

tests/baselines/reference/anyAsConstructor.js

@@ -18,4 +18,4 @@ var a = new x();
 var b = new x('hello');
 var c = new x(x);
 // grammar allows this for constructors
-var d = new x(x); // no error 
+var d = new x(x); // no error

tests/baselines/reference/anyAssignabilityInInheritance.js

@@ -135,4 +135,4 @@ var CC;
 })(CC || (CC = {}));
 var r3 = foo3(a); // any
 var r3 = foo3(a); // any
-var r3 = foo3(a); // any 
+var r3 = foo3(a); // any

tests/baselines/reference/arrayLiteralsWithRecursiveGenerics.js

@@ -56,4 +56,4 @@ var xs = [list, myList]; // {}[]
 var ys = [list, list2]; // {}[]
 var zs = [list, null]; // List<number>[]
 var myDerivedList;
-var as = [list, myDerivedList]; // List<number>[] 
+var as = [list, myDerivedList]; // List<number>[]

tests/baselines/reference/arrayOfFunctionTypes3.js

@@ -50,4 +50,4 @@ var b2;
 var c2;
 var z2 = [a2, b2, c2];
 var r6 = z2[0];
-var r7 = r6(''); // any not string 
+var r7 = r6(''); // any not string

tests/baselines/reference/arrayTypeOfFunctionTypes.js

@@ -29,4 +29,4 @@ var r4b = new r3(); // error
 var x3;
 var r5 = x2[1];
 var r6 = r5();
-var r6b = new r5(); // error 
+var r6b = new r5(); // error

tests/baselines/reference/assignmentToObjectAndFunction.js

@@ -59,4 +59,4 @@ var bad;
 (function (bad) {
     bad.apply = 0;
 })(bad || (bad = {}));
-var badFundule = bad; // error 
+var badFundule = bad; // error

tests/baselines/reference/augmentedTypeAssignmentCompatIndexSignature.js

@@ -26,4 +26,4 @@ var o = {};
 var f = function () {
 };
 var v1 = o; // Should be allowed
-var v2 = f; // Should be allowed 
+var v2 = f; // Should be allowed