Question: I have a [vuex](https://vuex.vuejs.org/en/intro.html) store, like following:

```
import spreeApi from '../../gateways/spree-api'
// initial state
const state = {
  products: [],
  categories: []
}

// mutations
const mutations = {
 SET_PRODUCTS: (state, response) => {
   state.products = response.data.products
   commit('SET_CATEGORIES')
 },
 SET_CATEGORIES: (state) => {
   state.categories = state.products.map(function(product) { return product.category})
 }

}

const actions = {
 FETCH_PRODUCTS: (state, filters) => {
   return spreeApi.get('products').then(response => state.commit('SET_PRODUCTS', response))
 }
}

export default {
  state,
  mutations,
  actions
}

```

I want to call mutation: `SET_CATEGORIES` from mutation: `SET_PRODUCTS`, But this gives me error: 

> 
> projectFilter.js:22 Uncaught (in promise) ReferenceError: commit is not defined(…)
> 
> 
> 

What should be correct way to do this. I tried `store.commit` and `this.commit`, but these also gave similar errors.

Answer: 
When you are already doing a mutation, there is no way to `commit` another mutation. A mutation is a synchronous call which changes the state. Within one mutation, you will not be able to commit another mutation.

Here is the API reference for Vuex: <https://vuex.vuejs.org/en/api.html>

As you can see, a mutation handler receives only `state` and `payload`, nothing more. Therefore you are getting `commit` as `undefined`.

In your case above, you can set the PRODUCT and CATEGORIES as part of the same mutation handler as a single commit. You can try if the following code works:

```js
// mutations
const mutations = {
    SET_PRODUCTS_AND_CATEGORIES: (state, response) => {
        state.products = response.data.products
        state.categories = state.products.map(function(product) { return product.category})
    },
    // ...
}

```

**EDIT:** Please refer to the answer below, provided by *Daniel S. Deboer*. The correct method is to commit two mutations from a single action, as described in his [answer](https://stackoverflow.com/a/43147938/10839134).
To share code between mutations, you must create a new function that performs the work, which you can then reuse. Fortunately, mutations are just plain old functions, and we can pass the `state` parameter around however we like, so this is quite easy to do.

For example:

```js
const mutations = {
 SET_PRODUCTS: (state, response) => {
   state.products = response.data.products
   setCategories(state)
 },
 SET_CATEGORIES: (state) => {
   setCategories(state)
 }
}

function setCategories(state) {
  state.categories = state.products.map(product => product.category)
}

```