diff --git a/lib/type.js b/lib/type.js
index 5e01f7e..dda695f 100644
--- a/lib/type.js
+++ b/lib/type.js
@@ -1,23 +1,21 @@
-var type = function (s) {
-    return Object.prototype.toString.call(s).slice(8, -1).toLowerCase();
-};
+const type = s =>
+  Object.prototype.toString
+    .call(s)
+    .slice(8, -1)
+    .toLowerCase();
 
-var types = [
-    'String',
-    'Array',
-    'Undefined',
-    'Boolean',
-    'Number',
-    'Function',
-    'Symbol',
-    'Object'
+const types = [
+  "String",
+  "Array",
+  "Undefined",
+  "Boolean",
+  "Number",
+  "Function",
+  "Symbol",
+  "Object"
 ];
 
-types.forEach(function (str) {
-    type['is' + str] = function (val) {
-        return type(val) === str.toLowerCase();
-    };
-});
-
-module.exports = type;
-
+module.exports = types.reduce((acc, str) => {
+  acc["is" + str] = val => type(val) === str.toLowerCase();
+  return acc;
+}, {});
diff --git a/spec/pxtorem-spec.js b/spec/pxtorem-spec.js
index ff422d4..2e4f63f 100644
--- a/spec/pxtorem-spec.js
+++ b/spec/pxtorem-spec.js
@@ -495,30 +495,36 @@ describe("filter-prop-list", function() {
   });
 });
 
-describe('exclude', function () {
-    it('should ignore file path with exclude RegEx', function () {
-        var options = {
-            exclude: /exclude/i
-        };
-        var processed = postcss(pxtorem(options)).process(basicCSS, { from: 'exclude/path' }).css;
-        expect(processed).toBe(basicCSS);
-    });
-
-    it('should not ignore file path with exclude String', function () {
-        var options = {
-            exclude: 'exclude'
-        };
-        var processed = postcss(pxtorem(options)).process(basicCSS, { from: 'exclude/path' }).css;
-        expect(processed).toBe(basicCSS);
-    });
-
-    it('should not ignore file path with exclude function', function () {
-        var options = {
-            exclude: function (file) {
-                return file.indexOf('exclude') !== -1;
-            }
-        };
-        var processed = postcss(pxtorem(options)).process(basicCSS, { from: 'exclude/path' }).css;
-        expect(processed).toBe(basicCSS);
-    });
+describe("exclude", function() {
+  it("should ignore file path with exclude RegEx", function() {
+    var options = {
+      exclude: /exclude/i
+    };
+    var processed = postcss(pxtorem(options)).process(basicCSS, {
+      from: "exclude/path"
+    }).css;
+    expect(processed).toBe(basicCSS);
+  });
+
+  it("should not ignore file path with exclude String", function() {
+    var options = {
+      exclude: "exclude"
+    };
+    var processed = postcss(pxtorem(options)).process(basicCSS, {
+      from: "exclude/path"
+    }).css;
+    expect(processed).toBe(basicCSS);
+  });
+
+  it("should not ignore file path with exclude function", function() {
+    var options = {
+      exclude: function(file) {
+        return file.indexOf("exclude") !== -1;
+      }
+    };
+    var processed = postcss(pxtorem(options)).process(basicCSS, {
+      from: "exclude/path"
+    }).css;
+    expect(processed).toBe(basicCSS);
+  });
 });