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[Vue.js] Better approach handling 'Do not mutate vuex store state outside mutation handlers' errors

Beforehand: My application is working as intended, but to know if there’s an better approach to the problem, I was having.

Situation: there is a project where when currently implemeneting a Permission-System. The current flow is, to load specific objects (lets take user in this case) and inject the permissions afterwards.

Problem: Getting ‘Do not mutate vuex store state outside mutation handlers.’ error inside vuex-action.

Question: Is there a better way to omit the error than my approach below?

Simplified it looks like this (here when getting my objects from our API and storing them in vuex-store):

// user.js (vuex-module)
state: {
user: null,
},
mutations: {
// …
setUser(state, user) {
state.user = user
}
}
actions: {
// … other vuex-actions
async login({commit, dispatch}, payload) {
let userFromDb = DbUtil.getUser(payload) // is an axios call to our api

// here the permissions get injected
// action in another vuex-module
dispatch(‘permissions/injectPermissions’, userFromDb)

// commiting to store
commit(‘setUser’, userFromDb)

return userFromDb
}
}

My permissions.js (here when injecting the permissions to my object):

// permissions.js (vuex-module)
actions: {
// … other vuex-actions

// payload = user in this example
async injectPermissions({commit, dispatch}, payload) {
let permissionFromDb = DbUtil.getPermissions(/* … */)

payload.permissions = permissionFromDb // -> Here when getting ‘Do not mutate vuex store state outside mutation handlers.’-Error, because `payload` == the user from user-state

return payload
}
}

Workaround: I added a mutation which changes the user-state object for me inside a mutation-handler.

mutations: {
/**
* A ‘set’-wrapper to mutate vuex-store variable inside a mutation to avoid getting a error.
* @param state
* @param payload:
* object - object to be mutated
* prop - prop inside object that is affected
* value - value that should be assigned
*/
setWrapper(state, payload) {
let { object, prop, value } = payload

object[prop] = value
}
}

The line where the error was thrown before gets changed to:

commit(‘setWrapper’, {
object: payload,
prop: ‘permissions’,
value: permissionFromDb
})

Solution :

Actions do not mutate the state.
Actions are there to perform asynchronous tasks.
When you want to change the state within an action, you have to rely on a mutation by using this synatx: commit(‘MUTATION_NAME’, payload)

Then:

MUATATION_NAME(state, payload) {
state.permissions = payload.permissions
}

This is the clean and right way.