fix: correctly dasherize cap suffixes

Co-authored-by: Mu-An Chiou <me@muanchiou.com>

Author: keithamus

src/register.ts

@@ -11,7 +11,7 @@ interface CustomElement {
  */
 export function register(classObject: CustomElement): void {
   const name = classObject.name
-    .replace(/([A-Z][a-z])/g, '-$1')
+    .replace(/([A-Z]($|[a-z]))/g, '-$1')
     .replace(/(^-|-Element$)/, '')
     .toLowerCase()
   if (!window.customElements.get(name)) {

test/register.js

@@ -34,6 +34,12 @@ describe('register', () => {
     expect(window.customElements.get('url-bar')).to.equal(URLBar)
   })
 
+  it('dasherizes cap suffixed names correctly', () => {
+    class ClipX {}
+    register(ClipX)
+    expect(window.customElements.get('clip-x')).to.equal(ClipX)
+  })
+
   it('automatically drops the `Element` suffix', () => {
     class ASuffixedElement {}
     register(ASuffixedElement)