Rails Deep Nested Attributes to Vue Instance with JSON

Question

I have a Rails app with nested form attributes and I'm using Vue.js. My first level nesting is working fine for creating and editing, but for deeper nested attributes, how can I rectify the issue of Rails needing "_attributes" appended to the associated attributes to process the update?

How can I access the deeper nested attributes (in my case, the "minimum_premia") and pass them to the Vue instance with the "_attributes" suffix so the submit goes through?

//_form.html.erb

<%= content_tag :div,
data: {
  id: product.id,
  product: product.to_json(except: [:id, :created_at, :updated_at]),
  coverages_attributes: product.coverages.to_json(:except => 
  [:product_id, :created_at, :updated_at], :include => [:minimum_premia 
  => {:except => [:coverage_id, :created_at, :updated_at]}])
} do %>

...

<div v-for="(minimum_premium, index) in coverage.minimum_premia_attributes">
  <label>Amount</label>
    <input type="number" v-model="minimum_premium.amount">
</div>


//vue.js

var id = element.dataset.id
var product = JSON.parse(element.dataset.product)
    var coverages_attributes = JSON.parse(element.dataset.coveragesAttributes)
    coverages_attributes.forEach(function(coverage) {coverage._destroy = null})
    product.coverages_attributes = coverages_attributes

var app = new Vue({
  el: element,
  data: function() {
      return { id: id, product: product }
  },
  methods: {
    addCoverage: function() {
      this.product.coverages_attributes.push({
        id: null,
        name: "", 
        _destroy: null,
        minimum_premia_attributes: [{
          id: null,
          amount: null
        }]
      })
    } 

Answer 1

This was solved using Jbuilder to generate a JSON object using the necessary appended names.

For example:

json.product do
  json.coverages_attributes product.coverages do |coverage|
    json.minimum_premium_rules_attributes coverage.minimum_premium_rules do |minimum_premium_rule|
      json.(minimum_premium_rule, :minimum_premium)
    end
  end
end

The coverage.minimum_premium_rules retrieved from the database were passed into vue using the proper nested attribute naming - minimum_premium_rules_attributes -that Rails needs to update the record.