Update

after/autoload/styledcomplete.vim

@@ -61,3 +61,24 @@ fun! styledcomplete#CompleteSC(findstart, base)
     return s:funcref(a:findstart, a:base)
   endif
 endfun
+if exists('g:polyglot_disabled') && index(g:polyglot_disabled, 'styled-components') != -1
+  finish
+endif
+
+" Vim completion script
+" Language:   styled-components (js/ts)
+" Maintainer: Karl Fleischmann <fleischmann.karl@gmail.com>
+" URL:        https://github.com/styled-components/vim-styled-components
+
+fun! styledcomplete#CompleteSC(findstart, base)
+  if IsStyledDefinition(line('.'))
+    return csscomplete#CompleteCSS(a:findstart, a:base)
+  endif
+
+  " Only trigger original omnifunc if it was set in the first place
+  if exists('b:prevofu')
+    " create a funcref to call with the previous omnicomplete function
+    let s:funcref = function(b:prevofu)
+    return s:funcref(a:findstart, a:base)
+  endif
+endfun