Support dasherizing symbols by using their descriptions

Author: keithamus

src/dasherize.ts

@@ -1,6 +1,14 @@
 export const dasherize = (str: unknown): string =>
-  String(str)
+  String(typeof str === 'symbol' ? str.description : str)
     .replace(/([A-Z]($|[a-z]))/g, '-$1')
     .replace(/--/g, '-')
     .replace(/^-|-$/, '')
     .toLowerCase()
+
+export const mustDasherize = (str: unknown, type = 'property'): string => {
+  const dashed = dasherize(str)
+  if (!dashed.includes('-')) {
+    throw new DOMException(`${type}: ${String(str)} is not a valid ${type} name`, 'SyntaxError')
+  }
+  return dashed
+}

test/dasherize.ts

@@ -8,10 +8,11 @@ describe('dasherize', () => {
     ['FooBar', 'foo-bar'],
     ['autofocusWhenReady', 'autofocus-when-ready'],
     ['URLBar', 'url-bar'],
-    ['ClipX', 'clip-x']
+    ['ClipX', 'clip-x'],
+    [Symbol('helloWorld'), 'hello-world']
   ]
 
   tests.map(([input, output]) =>
-    it(`transforms ${input} to ${output}`, () => expect(dasherize(input)).to.equal(output))
+    it(`transforms ${String(input)} to ${output}`, () => expect(dasherize(input)).to.equal(output))
   )
 })