diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 840e2a7e584..aaf3bf624b6 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -428,8 +428,8 @@ namespace ts {
             switch (token) {
                 case SyntaxKind.SingleLineCommentTrivia:
                 case SyntaxKind.MultiLineCommentTrivia:
-                    // replace comments with whitespaces to preserve original characters position
-                    output += replaceWithWhitespaces(scanner.getTokenText());
+                    // replace comments with whitespace to preserve original character positions
+                    output += scanner.getTokenText().replace(/\S/g, " ");
                     break;
                 default:
                     output += scanner.getTokenText();
@@ -437,30 +437,6 @@ namespace ts {
             }
         }
         return output;
-
-        function replaceWithWhitespaces(commentTokenText: string): string {
-            let result = "";
-            let pos = 0;
-            let start = 0;
-            while (pos < commentTokenText.length) {
-                if (isLineBreak(commentTokenText.charCodeAt(pos))) {
-                    let nbCharToReplace = pos - start;
-                    result += nSpaces(nbCharToReplace);
-                    result += commentTokenText.charAt(pos);
-                    pos += 1;
-                    start = pos;
-                }
-                else {
-                    pos += 1;
-                }
-            }
-            result += nSpaces(pos - start);
-            return result;
-
-            function nSpaces(n: number): string {
-                return new Array(n + 1).join(" ");
-            };
-        }
     }
 
 
diff --git a/tests/cases/unittests/tsconfigParsing.ts b/tests/cases/unittests/tsconfigParsing.ts
index 7490b525000..3603d22f314 100644
--- a/tests/cases/unittests/tsconfigParsing.ts
+++ b/tests/cases/unittests/tsconfigParsing.ts
@@ -1,86 +1,86 @@
 /// <reference path="..\..\..\src\harness\harness.ts" />
 /// <reference path="..\..\..\src\compiler\commandLineParser.ts" />
 
-module ts {
-  describe('parseConfigFileTextToJson', () => {
-    function assertParseResult(jsonText: string, expectedConfigObject: { config?: any; error?: Diagnostic }) {
-      let parsed = ts.parseConfigFileTextToJson("/apath/tsconfig.json", jsonText);
-      assert.equal(JSON.stringify(parsed), JSON.stringify(expectedConfigObject));
-    }
-    
-    function assertParseError(jsonText: string) {     
-       let parsed = ts.parseConfigFileTextToJson("/apath/tsconfig.json", jsonText);
-       assert.isTrue(undefined === parsed.config);    
-       assert.isTrue(undefined !== parsed.error);     
-    }
+namespace ts {
+    describe('parseConfigFileTextToJson', () => {
+        function assertParseResult(jsonText: string, expectedConfigObject: { config?: any; error?: Diagnostic }) {
+            let parsed = ts.parseConfigFileTextToJson("/apath/tsconfig.json", jsonText);
+            assert.equal(JSON.stringify(parsed), JSON.stringify(expectedConfigObject));
+        }
 
-    it("returns empty config for file with only whitespaces", () => {
-    	assertParseResult("", { config : {} });
-      assertParseResult(" ", { config : {} });
-    });
-    
-    it("returns empty config for file with comments only", () => {
-      assertParseResult("// Comment", { config: {} });
-      assertParseResult("/* Comment*/", { config: {} });
-    });
+        function assertParseError(jsonText: string) {
+             let parsed = ts.parseConfigFileTextToJson("/apath/tsconfig.json", jsonText);
+             assert.isTrue(undefined === parsed.config);
+             assert.isTrue(undefined !== parsed.error);
+        }
 
-    it("returns empty config when config is empty object", () => {
-      assertParseResult("{}", { config: {} });
-    });
+        it("returns empty config for file with only whitespaces", () => {
+            assertParseResult("", { config : {} });
+            assertParseResult(" ", { config : {} });
+        });
 
-    it("returns config object without comments", () => {
-      assertParseResult(
-      	`{ // Excluded files
-      		"exclude": [
-  					// Exclude d.ts
-  					"file.d.ts"
-  				]
-      	}`, { config: { exclude: ["file.d.ts"] } });
-    
-      assertParseResult(
-        `{
-      		/* Excluded
-             Files
-          */
-      		"exclude": [  		
-  					/* multiline comments can be in the middle of a line */"file.d.ts"
-  				]
-      	}`, { config: { exclude: ["file.d.ts"] } });
-    });
+        it("returns empty config for file with comments only", () => {
+            assertParseResult("// Comment", { config: {} });
+            assertParseResult("/* Comment*/", { config: {} });
+        });
 
-    it("keeps string content untouched", () => {
-      assertParseResult(
-        `{
-      		"exclude": [
-            "xx//file.d.ts"
-  				]
-      	}`, { config: { exclude: ["xx//file.d.ts"] } });
-     assertParseResult(
-        `{
-      		"exclude": [
-  					"xx/*file.d.ts*/"
-  				]
-      	}`, { config: { exclude: ["xx/*file.d.ts*/"] } });
+        it("returns empty config when config is empty object", () => {
+            assertParseResult("{}", { config: {} });
+        });
+
+        it("returns config object without comments", () => {
+            assertParseResult(
+                `{ // Excluded files
+                    "exclude": [
+                        // Exclude d.ts
+                        "file.d.ts"
+                    ]
+                }`, { config: { exclude: ["file.d.ts"] } });
+
+            assertParseResult(
+                `{
+                    /* Excluded
+                         Files
+                    */
+                    "exclude": [
+                        /* multiline comments can be in the middle of a line */"file.d.ts"
+                    ]
+                }`, { config: { exclude: ["file.d.ts"] } });
+        });
+
+        it("keeps string content untouched", () => {
+            assertParseResult(
+                `{
+                    "exclude": [
+                        "xx//file.d.ts"
+                    ]
+                }`, { config: { exclude: ["xx//file.d.ts"] } });
+         assertParseResult(
+                `{
+                    "exclude": [
+                        "xx/*file.d.ts*/"
+                    ]
+                }`, { config: { exclude: ["xx/*file.d.ts*/"] } });
+        });
+
+        it("handles escaped characters in strings correctly", () => {
+            assertParseResult(
+                `{
+                    "exclude": [
+                        "xx\\"//files"
+                    ]
+                }`, { config: { exclude: ["xx\"//files"] } });
+
+            assertParseResult(
+                `{
+                    "exclude": [
+                        "xx\\\\" // end of line comment
+                    ]
+                }`, { config: { exclude: ["xx\\"] } });
+         });
+
+        it("returns object with error when json is invalid", () => {
+             assertParseError("invalid");
+        });
     });
-    
-    it("handles escaped characters in strings correctly", () => {
-      assertParseResult(
-        `{
-      		"exclude": [
-  					"xx\\"//files"
-  				]
-      	}`, { config: { exclude: ["xx\"//files"] } });
-        
-      assertParseResult(
-        `{
-      		"exclude": [
-  					"xx\\\\" // end of line comment
-  				]
-      	}`, { config: { exclude: ["xx\\"] } });
-     });
-    
-    it("returns object with error when json is invalid", () => {
-       assertParseError("invalid");      
-    });
-  });
 }