How to use Nuxt $auth inside an axios plugin (How to add Token to all axios requests) - authentication

Question

Im looking to use $auth inside my Nuxt project, specially inside an axios plugin.
Here is my code:
plugins/api.js
export default function ({ $axios }, inject) {
const api = $axios.create({
headers: {
common: {
Accept: 'text/plain, */*',
},
},
})
// Set baseURL to something different
api.setBaseURL('http://localhost:4100/')
// Inject to context as $api
inject('api', api)
}
Now the problem comes when I try to use $auth from #nuxtjs/auth-next package.
As stated in the docs:
This module globally injects $auth instance, meaning that you can
access it anywhere using this.$auth. For plugins, asyncData, fetch,
nuxtServerInit and Middleware, you can access it from context.$auth.
I tried the following:
This results in $auth being undefined
export default function ({ $axios, $auth }, inject) {
This one was near
export default function ({ $axios, app }, inject) {
console.log(app) //This one logs $auth in the object logged
console.log(app.$auth) // I don't understand why but this one returns undefined
My main goal here is to make use of this.$auth.strategy.token.get()and pass it (if the token exists of course) to the headers of every request made using this.$api
I have been looking for similar questions and answers but none has helped me to solve this, I could just add the token every time I write this.$api but that would increase the code unnecessarily.
Thanks in advance to all the people for your time and help.
EDIT:
Okay, now I made a test. and the next code is actually logging the $auth object correctly, it seems some time is needed to make it work but now Im afraid that using setTimeout could cause an error because I can't know exactly how much time is needed for $auth to be available.
export default function ({ $axios, app }, inject) {
setTimeout(() => {
console.log('After timeout', app.$auth)
}, 50)
EDIT 2:
So now I have made more tests, and using 0 milliseconds instead of 50 works too, so I will use setTimeout with 0 milliseconds for now, I hope anyone find a better solution or explain why $auth is not available before using setTimeout so I can decide what to do with my code.
EDIT 3:
After trying to wrap all my previous code inside setTimeout I noticed that the code fails, so that isn't a solution.

Answer 1

I have found a solution so I will post it so that every person that could have the same problem in the future can solve it.
It turns out that I could easily solve it using interceptors.
export default function ({ $axios, app }, inject) {
// At this point app.$auth is undefined. (Unless you use setTimeout but that is not a solution)
//Create axios instance
const api = $axios.create({
headers: {
common: {
Accept: 'application/json', //accept json
},
},
})
// Here is the magic, onRequest is an interceptor, so every request made will go trough this, and then we try to access app.$auth inside it, it is defined
api.onRequest((config) => {
// Here we check if user is logged in
if (app.$auth.loggedIn) {
// If the user is logged in we can now get the token, we get something like `Bearer yourTokenJ9F0JFODJ` but we only need the string without the word **Bearer**, So we split the string using the space as a separator and we access the second position of the array **[1]**
const token = app.$auth.strategy.token.get().split(' ')[1]
api.setToken(token, 'Bearer') // Here we specify the token and now it works!!
}
})
// Set baseURL to something different
api.setBaseURL('http://localhost:4100/')
// Inject to context as $api
inject('api', api)
}

Answer 2

Also Nuxt Auth itself has provided a solution for this issue:
https://auth.nuxtjs.org/recipes/extend/