Vue.js: Nuxt error handling

Question

Struggling a bit to set up error handling with vuex. There seems to be quite a few ways to do so and little documentation on proper error handling. I've been experimenting with four alternatives, though I haven't found a satisfying solution yet.

---

Alternative 1 - Catching and processing errors on component

in pages/login.vue:

export default {
    methods: {
        onLogin() {
            this.$store.dispatch('auth/login', {
                email: this.email,
                password: this.password,
            }).then(() => {
                this.$router.push('/home');
            }).catch((error) {
                // handle error in component
            });
        },
    },
}

in store/auth.js:

export const actions = {
    login({ commit }, { email, password }) {
        return this.$axios.post('/api/login', {
            email,
            password,
        }).then((res) => {
            doSomething(res);
        });
    },
}

PROS

• Hmm.

CONS

• Errors not handled and stored in vuex.
• Introduces lots of boilerplate code in component methods.

---

Alternative 2 - Catching and processing errors in vuex

in pages/login.vue:

export default {
    methods: {
        onLogin() {
            this.$store.dispatch('auth/login', {
                email: this.email,
                password: this.password,
            }).then(() => {
                this.$router.push('/home');
            });
        },
    },
}

in store/auth.js:

export const actions = {
    login({ commit }, { email, password }) {
        return this.$axios.post('/api/login', {
            email,
            password,
        }).then((res) => {
            doSomething(res);
        }).catch((error) => {
            // store error in application state
            commit('SET_ERROR', error);
        });
    },
}

PROS

• Error object is accessible with vuex from any component
• Could use a reactive error component in layout, which is revealed when the error state changes.

CONS

• I'm not sure if there is a way to track the source of the error, from which component it was thrown.

---

Alternative 3 - Catching errors using axios interceptors

in plugins/axios.js:

export default function({ $axios, store }) {
    $axios.onError(error => {
        store.dispatch('setError', error);
    });
}

in pages/login.vue:

export default {
    methods: {
        onLogin() {
            this.$store.dispatch('auth/login', {
                email: this.email,
                password: this.password,
            }).then(() => {
                this.$router.push('/home');
            });
        },
    },
}

in store/auth.js:

export const actions = {
    login({ commit }, { email, password }) {
        return this.$axios.post('/api/login', {
            email,
            password,
        }).then((res) => {
            doSomething(res);
        });
    },
}

PROS

• Global error handling
• No need to catch errors in either vuex or component
• No boiler-plate code

CONS

• All exceptions are unhandled, meaning non-axios errors are uncaught.

---

Alternative 4 - Custom error plugin

I've been experimenting in implementing a custom plugin that catches all exceptions, but I'm not succeeding in making it work.

in plugins/catch.js:

export default (ctx, inject) => {
    const catchPlugin = function (func) {
        return async function (args) {
            try {
                await func(args)
            } catch (e) {
                return console.error(e)
            }
        }
    };
    ctx.$catch = catchPlugin;
    inject('catch', catchPlugin);
}

in pages/login.vue:

export default {
    methods: {
        onLogin: this.$catch(async function () {
            await this.$store.dispatch('auth/login', { email: this.email, password: this.password });
            this.$router.push('/home');
        }),
    },
}

PROS

• No boilerplate.
• All errors caught in plugin.

CONS

• I cannot make it work. :(

---

My impression is that there is a lack of documentation on error handling in vue/nuxt. Could anyone get the fourth alternative to work? Would this be ideal? Any other alternatives? What is conventional?

Thank you for your time!

Answer 1

Use Promise in action

Example in vuex:

NEW_AUTH({ commit }) {
    return new Promise((resolve, reject) => {
      this.$axios.$get('/token').then((res) => {
        ...
        resolve();
      }).catch((error) => {
        reject(error);
      })
    })
  }

In page:

this.$store.dispatch('NEW_AUTH')
   .then(() => ... )
   .catch((error) => ... )

Answer 2

To address the Con from Alternative 2 you can either

(a) pass in the name of the component or even a reference to the component or

(b) you can persist the error in the state for the component that made the call. Then in your component you could check if there is an error and display it. For that you could use a mixin to forgo the need for boiler plate.,

in store/auth.js:

export const actions = {
    login({ commit }, { email, password }) {
        return this.$axios.post('/api/login', {
            email,
            password,
        }).then((res) => {
            doSomething(res);
            commit('save_to_state', { response: res });
        }).catch((error) => {
            commit('save_to_state', { error });
        });
    },
}