diff --git a/.eslintrc b/.eslintrc
new file mode 100644
index 0000000..b2f6ec6
--- /dev/null
+++ b/.eslintrc
@@ -0,0 +1,12 @@
+ecmaFeatures:
+    modules: true
+
+env:
+    es6: true
+    browser: true
+
+extends:
+    "eslint:recommended"
+
+rules:
+    no-cond-assign: 0
diff --git a/package.json b/package.json
index 71179b0..9cabd06 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
   },
   "scripts": {
     "pretest": "mkdir -p build && node -e 'process.stdout.write(\"var version = \\\"\" + require(\"./package.json\").version + \"\\\"; export * from \\\"../index\\\"; export {version};\");' > build/bundle.js && rollup -f umd -u d3-timer -n d3_timer -o build/d3-timer.js -- build/bundle.js",
-    "test": "faucet `find test -name '*-test.js'`",
+    "test": "faucet `find test -name '*-test.js'` && eslint index.js src",
     "prepublish": "npm run test && uglifyjs build/d3-timer.js -c -m -o build/d3-timer.min.js && rm -f build/d3-timer.zip && zip -j build/d3-timer.zip -- LICENSE README.md build/d3-timer.js build/d3-timer.min.js"
   },
   "devDependencies": {
diff --git a/src/timer.js b/src/timer.js
index b7d4acc..83191da 100644
--- a/src/timer.js
+++ b/src/timer.js
@@ -44,7 +44,7 @@ Timer.prototype = timer.prototype = {
 
 export function timer(callback, delay, time) {
   return new Timer(callback, delay, time);
-};
+}
 
 export function timerFlush(time) {
   time = time == null ? Date.now() : +time;
@@ -58,7 +58,7 @@ export function timerFlush(time) {
   } finally {
     --frame;
   }
-};
+}
 
 function wake() {
   frame = timeout = 0;