[Vuejs]-Calling a Vuex mutation is taking too much time to load Content and also mutate

In my opinion the problem is not in a mutation, the problem is in a rendering. Probably you are trying to render a lot of HTML at once.

Scripting in JS comparing to operation on DOM is very fast and I don’t see possible perfomance issue in your code, so I’m geusing you are trying render to much HTML. To proof my theory you can use performance chrome dev tools and check how long time takes rendering and how long takes scripting.

If the ussue is in rendering you can try optimize your template for displaying HTML or you can implement paging and display less post per one page.