diff --git a/src/harness/tsconfig.json b/src/harness/tsconfig.json
index 37c24527730..5299b72bd27 100644
--- a/src/harness/tsconfig.json
+++ b/src/harness/tsconfig.json
@@ -15,15 +15,12 @@
         { "path": "../services" },
         { "path": "../jsTyping" },
         { "path": "../server" },
-        { "path": "../typingsInstallerCore" }
+        { "path": "../typingsInstallerCore" },
+        { "path": "../vfs" }
     ],
 
     "files": [
-        "collectionsImpl.ts",
         "util.ts",
-        "documentsUtil.ts",
-        "vpathUtil.ts",
-        "vfsUtil.ts",
         "compilerImpl.ts",
         "evaluatorImpl.ts",
         "fakesHosts.ts",
diff --git a/src/harness/collectionsImpl.ts b/src/vfs/collectionsImpl.ts
similarity index 100%
rename from src/harness/collectionsImpl.ts
rename to src/vfs/collectionsImpl.ts
diff --git a/src/harness/documentsUtil.ts b/src/vfs/documentsUtil.ts
similarity index 94%
rename from src/harness/documentsUtil.ts
rename to src/vfs/documentsUtil.ts
index c07142e794f..1a05a3ac36e 100644
--- a/src/harness/documentsUtil.ts
+++ b/src/vfs/documentsUtil.ts
@@ -2,13 +2,19 @@
 //       support the eventual conversion of harness into a modular system.
 
 namespace documents {
+    export interface HarnessCompilerTestFile {
+        unitName: string;
+        content: string;
+        fileOptions?: any;
+    }
+
     export class TextDocument {
         public readonly meta: Map<string, string>;
         public readonly file: string;
         public readonly text: string;
 
         private _lineStarts: readonly number[] | undefined;
-        private _testFile: Harness.Compiler.TestFile | undefined;
+        private _testFile: HarnessCompilerTestFile | undefined;
 
         constructor(file: string, text: string, meta?: Map<string, string>) {
             this.file = file;
@@ -20,7 +26,7 @@ namespace documents {
             return this._lineStarts || (this._lineStarts = ts.computeLineStarts(this.text));
         }
 
-        public static fromTestFile(file: Harness.Compiler.TestFile) {
+        public static fromTestFile(file: HarnessCompilerTestFile) {
             return new TextDocument(
                 file.unitName,
                 file.content,
@@ -184,4 +190,4 @@ namespace documents {
             return vlq;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/vfs/tsconfig.json b/src/vfs/tsconfig.json
new file mode 100644
index 00000000000..24012adea5b
--- /dev/null
+++ b/src/vfs/tsconfig.json
@@ -0,0 +1,25 @@
+{
+    "extends": "../tsconfig-base",
+    "compilerOptions": {
+        "outFile": "../../built/local/vfs.js",
+        "types": [
+            "node", "mocha", "chai"
+        ],
+        "lib": [
+            "es6",
+            "scripthost"
+        ]
+    },
+    "references": [
+        { "path": "../compiler" },
+        { "path": "../jsTyping" },
+        { "path": "../services" }
+    ],
+
+    "files": [
+        "collectionsImpl.ts",
+        "documentsUtil.ts",
+        "vpathUtil.ts",
+        "vfsUtil.ts"
+    ]
+}
diff --git a/src/harness/vfsUtil.ts b/src/vfs/vfsUtil.ts
similarity index 100%
rename from src/harness/vfsUtil.ts
rename to src/vfs/vfsUtil.ts
diff --git a/src/harness/vpathUtil.ts b/src/vfs/vpathUtil.ts
similarity index 100%
rename from src/harness/vpathUtil.ts
rename to src/vfs/vpathUtil.ts