Vuex is not defined

This error occurs when you try to use Vuex (a state management library for Vue.js) in your code without properly importing it or registering it as a plugin in your Vue.js application.

To fix this error, you need to make sure that Vuex is properly imported and registered in your Vue.js application. Here are some steps you can follow:

1. Install Vuex by running the following command in your terminal:

npm install vuex

2. Import Vuex in your main.js file (or wherever you want to use it) by adding the following line at the top:

import Vuex from 'vuex'

3. Register Vuex as a plugin in your Vue.js application by adding the following code to your main.js file:

Vue.use(Vuex)

4. Use Vuex in your components by importing it and creating a store instance. For example:

import Vuex from 'vuex'

const store = new Vuex.Store({
  state: {
    count: 0
  },
  mutations: {
    increment (state) {
      state.count++
    }
  }
})

export default {
  store: store,
  // rest of your component code
}

By following these steps, you should be able to use Vuex in your Vue.js application without encountering the "Vuex is not defined" error.