feat: guard for node

Author: kingyue737

src/index.js

@@ -88,7 +88,7 @@ export default (options = {}) => {
  /* if inject is enabled, we want to simply inject the stylesheet into the document head */
  if (options.inject) {
  return {
- code: `document.head.appendChild(document.createElement("style")).textContent=${JSON.stringify(transformedCode)};`,
+ code: `if(typeof document!=='undefined')document.head.appendChild(document.createElement("style")).textContent=${JSON.stringify(transformedCode)};`,
  map: null
  };
  }