How to make a form handling with vuex

#vue #javascript #todayilearned #refactorit

Problem

Let's say you want to save the input of your form on the state of vuex.

Maybe someone new to vuex would try something like this:

<input id="name" name="name" type="text" v-model="$store.state.user.name">

If you try this you will see that:

It doesn't work
Even if it worked, it is totally against the purpose of vuex, that is never have a change of state without it being made by a mutation.

Always send a mutation to change something.

Now, with that in mind, if you look into the documentation of vuex you will find the following:

[...] An alternative approach is using a two-way computed property with a setter:

<input v-model="message">

// ...
computed: {
  message: {
    get () {
      return this.$store.state.obj.message
    },
    set (value) {
      this.$store.commit('updateMessage', value)
    }
  }
}

click here to see.

You can use the v-model to change, but you will need to register a computed property with a getter and a setter to change the state.

Works?
Works.

But let's say you have a form, you will need to make a getter and a setter to every input. This works, but isn't practical.

The best way to do it, in my opinion, is to use the principles of clean code to make it:

export function mapFields(options) {
  const object = {};
  for (let x = 0; x < options.fields.length; x++) {
    const field = [options.fields[x]];
    object[field] = {
      get() {
        return this.$store.state[options.base][field];
      },
      set(value) {
        this.$store.commit(options.mutation, { [field]: value });
      }
    };
  }
  return object;
}

Where mapField is the function that map all the field and handle the form. Options is an object with a field which is the field you want to map and a base to refer.

At the end it will only return the getter and setter to us, not so different from before, but with a lot less code.

EDIT: I forgot to show how to use it, so here it is.

I would put it on some helper.js, so i can just import it from my userForm.vue, like this:

<script>
import { mapFields } from "@/helpers.js"

export default {
  computed: {
    ...mapFields({
    fields: ["name", "email", "street", "zipcode"],
    base: "user",
    mutation: "UPDATE_USER"
    }),
...

Hope you enjoyed my first post here, any questions comment bellow! 😎

Happy new year

Top comments (13)

Vamsi • Dec 30 '19

Thanks! This is exactly what I am looking for.
Where do you call the mapFields function. Could you please show an example?

Armstrong • Dec 31 '19

I think if you do something like

...

Then, in your methods you define the 'handleSubmi function as follows:

methods:{
handleSubmit(e){
e.preventDefault();
mapFields(e)
//...
}

I think something like the above would do... what do you think?

Matheus Gomes 👨‍💻 • Dec 31 '19

I would use it in the computed property, so i could change the state as i input .

Matheus Gomes 👨‍💻 • Dec 31 '19

My fault, I will edit the post to answer you, sorry for this and thanks for asking.

mordechairoth • Oct 22 '21

Thank you! for this amazing super cool solution. I was searching the web for a normal not redundant way to deal with forms when using Vuex and thank god I bumped into this post. This is an amazing and easy solution, thanks.

p.s. there's a syntax error in the example 'const fields = [options.fields[x]]', the outer square brackets should be removed.