diff --git a/Jakefile.js b/Jakefile.js
index bcc1f1dc650..5112a8db597 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -975,6 +975,8 @@ var servicesLintTargets = [
 });
 var lintTargets = compilerSources
     .concat(harnessCoreSources)
+    // Other harness sources
+    .concat(["instrumenter.ts"].map(function(f) { return path.join(harnessDirectory, f) }))
     .concat(serverCoreSources)
     .concat(["client.ts"].map(function(f) { return path.join(serverDirectory, f); }))
     .concat(tslintRulesFiles)
diff --git a/src/harness/instrumenter.ts b/src/harness/instrumenter.ts
index b1b1750b8a8..b8f42e7e8bd 100644
--- a/src/harness/instrumenter.ts
+++ b/src/harness/instrumenter.ts
@@ -1,6 +1,6 @@
-declare var require: any, process: any;
-var fs: any = require('fs');
-var path: any = require('path');
+declare const require: any, process: any;
+const fs: any = require("fs");
+const path: any = require("path");
 
 function instrumentForRecording(fn: string, tscPath: string) {
     instrument(tscPath, `
@@ -14,31 +14,31 @@ ts.sys = Playback.wrapSystem(ts.sys);
 ts.sys.startReplay("${ logFilename }");`);
 }
 
-function instrument(tscPath: string, prepareCode: string, cleanupCode: string = '') {
-    var bak = tscPath + '.bak';
+function instrument(tscPath: string, prepareCode: string, cleanupCode = "") {
+    const bak = `${tscPath}.bak`;
     fs.exists(bak, (backupExists: boolean) => {
-        var filename = tscPath;
+        let filename = tscPath;
         if (backupExists) {
             filename = bak;
         }
 
-        fs.readFile(filename, 'utf-8', (err: any, tscContent: string) => {
+        fs.readFile(filename, "utf-8", (err: any, tscContent: string) => {
             if (err) throw err;
 
             fs.writeFile(bak, tscContent, (err: any) => {
                 if (err) throw err;
 
-                fs.readFile(path.resolve(path.dirname(tscPath) + '/loggedIO.js'), 'utf-8', (err: any, loggerContent: string) => {
+                fs.readFile(path.resolve(path.dirname(tscPath) + "/loggedIO.js"), "utf-8", (err: any, loggerContent: string) => {
                     if (err) throw err;
 
-                    var invocationLine = 'ts.executeCommandLine(ts.sys.args);';
-                    var index1 = tscContent.indexOf(invocationLine);
+                    const invocationLine = "ts.executeCommandLine(ts.sys.args);";
+                    const index1 = tscContent.indexOf(invocationLine);
                     if (index1 < 0) {
-                        throw new Error("Could not find " + invocationLine);
+                        throw new Error(`Could not find ${invocationLine}`);
                     }
 
-                    var index2 = index1 + invocationLine.length;
-                    var newContent = tscContent.substr(0, index1) + loggerContent + prepareCode + invocationLine + cleanupCode + tscContent.substr(index2) + '\r\n';
+                    const index2 = index1 + invocationLine.length;
+                    const newContent = tscContent.substr(0, index1) + loggerContent + prepareCode + invocationLine + cleanupCode + tscContent.substr(index2) + "\r\n";
                     fs.writeFile(tscPath, newContent);
                 });
             });
@@ -46,15 +46,16 @@ function instrument(tscPath: string, prepareCode: string, cleanupCode: string =
     });
 }
 
-var isJson = (arg: string) => arg.indexOf(".json") > 0;
+const isJson = (arg: string) => arg.indexOf(".json") > 0;
 
-var record = process.argv.indexOf('record');
-var tscPath = process.argv[process.argv.length - 1];
+const record = process.argv.indexOf("record");
+const tscPath = process.argv[process.argv.length - 1];
 if (record >= 0) {
-    console.log('Instrumenting ' + tscPath + ' for recording');
+    console.log(`Instrumenting ${tscPath} for recording`);
     instrumentForRecording(process.argv[record + 1], tscPath);
-} else if (process.argv.some(isJson)) {
-    var filename = process.argv.filter(isJson)[0];
+}
+else if (process.argv.some(isJson)) {
+    const filename = process.argv.filter(isJson)[0];
     instrumentForReplay(filename, tscPath);
 }