merge and deduplicate class names

packages/nuemark/src/parse-tag.js

@@ -10,9 +10,11 @@ export function parseTag(input) {
   const specs = strings.filter((s, i) => !i || s.match(/^[#|.]/)).join('')
   const attribs = strings.filter(s => !specs.includes(s))
   const self = { ...parseSpecs(specs), data: {} }
-
+  const classes = new Set((self.attr?.class || '').split(' '))
 
   function set(key, val) {
+    if (key == 'class') return val.split(' ').forEach(v => classes.add(v))
+
     const ctx = ATTR.includes(key) || key.startsWith('data-') ? 'attr' : 'data'
     self[ctx][key] = val
   }
@@ -30,6 +32,8 @@ export function parseTag(input) {
     else set('_', getValue(key) || key)
   }
 
+  if (classes.size) self.attr.class = [...classes].join(' ')
+
   return self
 }
 
@@ -76,9 +80,9 @@ export function parseAttr(str) {
   const attr = {}
 
   // classes
-  const classes = []
-  str.replace(/\.([\w\-]+)/g, (_, el) => classes.push(el))
-  if (classes[0]) attr.class = classes.join(' ')
+  const classes = new Set()
+  str.replace(/\.([\w\-]+)/g, (_, el) => classes.add(el))
+  if (classes.size) attr.class = [...classes].join(' ')
 
   // id
   str.replace(/#([\w\-]+)/, (_, el) => attr.id = el)

packages/nuemark/test/block.test.js

@@ -233,6 +233,12 @@ test('complex tag data', () => {
   expect(comp.data).toEqual({ world: true, size: 10, foo: "bar", })
 })
 
+test('duplicate tag classes', () => {
+  const { blocks } = parseBlocks(['[hello.c.c.bar class="foo bar" world]'])
+  expect(blocks[0].attr.class).toBe('c bar foo')
+  expect(blocks[0].data).toEqual({ world: true })
+})
+
 test('escaping', () => {
   const html = renderLines([
     '\\[code]', '',