diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index a9f40ab053c..cd05bb0b2c8 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -530,14 +530,14 @@ namespace ts {
                 }
 
                 function parseListTypeOption(opt: CommandLineOptionOfListType, value: string): (number | string)[] {
-                    const values = (value || "").split(",").filter(v => { return v != undefined; });
+                    const values = (value.trim() || "").split(",");
                     switch (opt.element.type) {
                         case "number":
                             return ts.map(values, parseInt);
                         case "string":
                             return ts.map(values, v => v || "");
                         default:
-                            return ts.map(values, v => parseCustomTypeOption(<CommandLineOptionOfCustomType>opt.element, v)).filter(v => { return v != undefined; });
+                            return ts.filter(ts.map(values, v => parseCustomTypeOption(<CommandLineOptionOfCustomType>opt.element, v)), v => !!v);
                     }
                 }
             }
@@ -793,6 +793,6 @@ namespace ts {
     }
 
     function convertJsonOptionOfListType(option: CommandLineOptionOfListType, values: any[], basePath: string, errors: Diagnostic[]): any[] {
-        return ts.map(values, v => convertJsonOption(option.element, v, basePath, errors)).filter(v => { return v != undefined; });
+        return ts.filter(ts.map(values, v => convertJsonOption(option.element, v, basePath, errors)), v => !!v);
     }
 }
diff --git a/tests/cases/unittests/commandLineParsing.ts b/tests/cases/unittests/commandLineParsing.ts
index a77d1e56494..275bba54f01 100644
--- a/tests/cases/unittests/commandLineParsing.ts
+++ b/tests/cases/unittests/commandLineParsing.ts
@@ -94,6 +94,26 @@ namespace ts {
                 });
         });
 
+        it("Parse incorrect form of library flags with trailing white-space ", () => {
+            // --lib es5, es7 0.ts
+            assertParseResult(["--lib", "es5, ", "es7", "0.ts"],
+                {
+                    errors: [{
+                        messageText: "",
+                        category: ts.Diagnostics.Arguments_for_library_option_must_be_Colon_0.category,
+                        code: ts.Diagnostics.Arguments_for_library_option_must_be_Colon_0.code,
+
+                        file: undefined,
+                        start: undefined,
+                        length: undefined,
+                    }],
+                    fileNames: ["es7", "0.ts"],
+                    options: {
+                        lib: ["lib.es5.d.ts"]
+                    }
+                });
+        });
+
         it("Parse multiple compiler flags with input files at the end", () => {
             // --lib es5,es6.symbol.wellknown --target es5 0.ts
             assertParseResult(["--lib", "es5,es6.symbol.wellknown", "--target", "es5", "0.ts"],