Summary

in #2033, introduced a useEffect hook to get initialData (after rendering)

 useEffect(() => {
    initPageData(window.location.pathname).then(pageData => {
      setData(pageData);
    });
  }, []);

before this pr

1. beforeHydration, initialData: null, render the html

2. afterHydration, hydrate the html

3. useEffect, get initialData and render the html again

so we get two html in the same page

after this pr

1. beforeHydration, initialData: {...}, render the html

2. afterHydration, hydrate the html successfully

Related Issue

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).