diff --git a/lib/main.js b/lib/main.js
index 5812e0d6..45a54e93 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -23,8 +23,8 @@ const Lambda = function () {
 }
 
 Lambda.prototype._createSampleFile = function (file, boilerplateName) {
-  var exampleFile = path.join(process.cwd(), file)
-  var boilerplateFile = path.join(
+  const exampleFile = path.join(process.cwd(), file)
+  const boilerplateFile = path.join(
     __dirname,
     (boilerplateName || file) + '.example'
   )
@@ -150,7 +150,7 @@ so you can easily test run multiple events.
 }
 
 Lambda.prototype._params = function (program, buffer) {
-  var params = {
+  const params = {
     FunctionName: program.functionName +
       (program.environment ? '-' + program.environment : '') +
       (program.lambdaVersion ? '-' + program.lambdaVersion : ''),
@@ -189,8 +189,8 @@ Lambda.prototype._params = function (program, buffer) {
     }
   }
   if (program.configFile) {
-    var configValues = fs.readFileSync(program.configFile)
-    var config = dotenv.parse(configValues)
+    const configValues = fs.readFileSync(program.configFile)
+    const config = dotenv.parse(configValues)
     // If `configFile` is an empty file, `config` value will be `{}`
     params.Environment = {
       Variables: config
@@ -441,8 +441,8 @@ Lambda.prototype._cleanDirectory = (codeDirectory) => {
 }
 
 Lambda.prototype._setRunTimeEnvironmentVars = function (program) {
-  var configValues = fs.readFileSync(program.configFile)
-  var config = dotenv.parse(configValues)
+  const configValues = fs.readFileSync(program.configFile)
+  const config = dotenv.parse(configValues)
 
   for (let k in config) {
     if (!config.hasOwnProperty(k)) {
diff --git a/test/main.js b/test/main.js
index 9b54baf6..cd2ec398 100644
--- a/test/main.js
+++ b/test/main.js
@@ -152,28 +152,28 @@ describe('lib/main', function () {
     const functionNamePattern =
       /(arn:aws:lambda:)?([a-z]{2}-[a-z]+-\d{1}:)?(\d{12}:)?(function:)?([a-zA-Z0-9-_]+)(:(\$LATEST|[a-zA-Z0-9-_]+))?/
     it('appends environment to original functionName', function () {
-      var params = lambda._params(program)
+      const params = lambda._params(program)
       assert.equal(params.FunctionName, '___node-lambda-development')
       assert.match(params.FunctionName, functionNamePattern)
     })
 
     it('appends environment to original functionName (production)', function () {
       program.environment = 'production'
-      var params = lambda._params(program)
+      const params = lambda._params(program)
       assert.equal(params.FunctionName, '___node-lambda-production')
       assert.match(params.FunctionName, functionNamePattern)
     })
 
     it('appends version to original functionName', function () {
       program.lambdaVersion = '2015-02-01'
-      var params = lambda._params(program)
+      const params = lambda._params(program)
       assert.equal(params.FunctionName, '___node-lambda-development-2015-02-01')
       assert.match(params.FunctionName, functionNamePattern)
     })
 
     it('appends version to original functionName (value not allowed by AWS)', function () {
       program.lambdaVersion = '2015.02.01'
-      var params = lambda._params(program)
+      const params = lambda._params(program)
       assert.equal(params.FunctionName, '___node-lambda-development-2015_02_01')
       assert.match(params.FunctionName, functionNamePattern)
     })
@@ -181,7 +181,7 @@ describe('lib/main', function () {
     it('appends VpcConfig to params when vpc params set', function () {
       program.vpcSubnets = 'subnet-00000000,subnet-00000001,subnet-00000002'
       program.vpcSecurityGroups = 'sg-00000000,sg-00000001,sg-00000002'
-      var params = lambda._params(program)
+      const params = lambda._params(program)
       assert.equal(params.VpcConfig.SubnetIds[0], program.vpcSubnets.split(',')[0])
       assert.equal(params.VpcConfig.SubnetIds[1], program.vpcSubnets.split(',')[1])
       assert.equal(params.VpcConfig.SubnetIds[2], program.vpcSubnets.split(',')[2])
@@ -191,7 +191,7 @@ describe('lib/main', function () {
     })
 
     it('does not append VpcConfig when params are not set', function () {
-      var params = lambda._params(program)
+      const params = lambda._params(program)
       assert.equal(Object.keys(params.VpcConfig.SubnetIds).length, 0)
       assert.equal(Object.keys(params.VpcConfig.SecurityGroupIds).length, 0)
     })
@@ -206,7 +206,7 @@ describe('lib/main', function () {
 
     it('does not append DeadLetterConfig when params are not set', function () {
       delete program.deadLetterConfigTargetArn
-      var params = lambda._params(program)
+      const params = lambda._params(program)
       assert.isNull(params.DeadLetterConfig.TargetArn)
     })
 
@@ -236,19 +236,19 @@ describe('lib/main', function () {
 
       it('adds variables when configFile param is set', function () {
         program.configFile = 'tmp.env'
-        var params = lambda._params(program)
+        const params = lambda._params(program)
         assert.equal(params.Environment.Variables['FOO'], 'bar')
         assert.equal(params.Environment.Variables['BAZ'], 'bing')
       })
 
       it('when configFile param is set but it is an empty file', function () {
         program.configFile = 'empty.env'
-        var params = lambda._params(program)
+        const params = lambda._params(program)
         assert.equal(Object.keys(params.Environment.Variables).length, 0)
       })
 
       it('does not add when configFile param is not set', function () {
-        var params = lambda._params(program)
+        const params = lambda._params(program)
         assert.isNull(params.Environment.Variables)
       })
     })