feat(extractor): split backslash (#1371)

Co-authored-by: Anthony Fu <anthonyfu117@hotmail.com>

packages/core/src/extractors/split.ts

@@ -1,7 +1,7 @@
 import type { Extractor } from '../types'
 import { isValidSelector } from '../utils'
 
-export const splitCode = (code: string) => code.split(/[\s'"`;=]+/g).filter(isValidSelector)
+export const splitCode = (code: string) => code.split(/\\?[\s'"`;=]+/g).filter(isValidSelector)
 
 export const extractorSplit: Extractor = {
   name: 'split',

test/extractor.test.ts

@@ -0,0 +1,21 @@
+import { extractorSplit } from '@unocss/core'
+import { expect, it } from 'vitest'
+
+it('extractorSplit', async () => {
+  let code = ''
+  async function extract() {
+    return [...await extractorSplit.extract({ code, original: code }) || []]
+  }
+
+  code = 'foo'
+  expect(await extract()).eql(['foo'])
+
+  code = '<div class="text-red border">foo</div>'
+  expect(await extract()).toContain('text-red')
+
+  code = '<div class="<sm:text-lg">foo</div>'
+  expect(await extract()).toContain('<sm:text-lg')
+
+  code = '"class=\"bg-white\""'
+  expect(await extract()).toContain('bg-white')
+})