cypress/integration/.eslintrc

@@ -1,4 +1,7 @@
 {
+  "parserOptions": {
+    "ecmaVersion": 2018
+  },
   "env": {
     "browser": false
   },

cypress/integration/headroom.spec.js

@@ -288,4 +288,37 @@ describe("Headroom", function() {
       });
     });
   });
+
+  describe("handling options and defaults", () => {
+    it("merges our own classes and preserves other defaults", () => {
+      const classes = {
+        initial: "foo",
+        pinned: "foo--pinned"
+      };
+
+      initialiseHeadroom({ classes });
+
+      cy.window().then(win => {
+        expect(win.hr.classes).to.deep.contain(classes);
+        const { initial, pinned, ...defaultClasses } = win.hr.classes;
+        expect(win.hr.classes).to.deep.contain(defaultClasses);
+      });
+    });
+
+    it("assigns default classes if no options supplied", () => {
+      initialiseHeadroom();
+
+      cy.window().then(win => {
+        expect(win.hr.classes).to.deep.equal(win.Headroom.options.classes);
+      });
+    });
+
+    it("assigns default classes if no no classes supplied", () => {
+      initialiseHeadroom({ tolerance: 5 });
+
+      cy.window().then(win => {
+        expect(win.hr.classes).to.deep.equal(win.Headroom.options.classes);
+      });
+    });
+  });
 });

package.json

@@ -1,6 +1,6 @@
 {
   "name": "headroom.js",
-  "version": "0.10.0",
+  "version": "0.10.2",
   "description": "Give your page some headroom. Hide your header until you need it",
   "main": "dist/headroom.js",
   "files": [

src/Headroom.js

@@ -16,7 +16,7 @@ function normalizeTolerance(t) {
 function Headroom(elem, options) {
   options = options || {};
   Object.assign(this, Headroom.options, options);
-  Object.assign(this.classes, Headroom.options.classes, options.classes);
+  this.classes = Object.assign({}, Headroom.options.classes, options.classes);
 
   this.elem = elem;
   this.tolerance = normalizeTolerance(this.tolerance);