Play vue.js with constant value in SailsJS

<ajax-form action="submitSomething"
    :cloud-error.sync="cloudError"
    :handle-parsing="handleParsingForm"
    @submitted="submittedForm()">
    <input type="text" v-model="someInput" >
    <ajax-button type="submit" :syncing="syncing" class="btn btn-dark">Submit Something</ajax-button>
</ajax-form>

parasails.registerPage('test-page', {
  //  ╦╔╗╔╦╔╦╗╦╔═╗╦    ╔═╗╔╦╗╔═╗╔╦╗╔═╗
  //  ║║║║║ ║ ║╠═╣║    ╚═╗ ║ ╠═╣ ║ ║╣
  //  ╩╝╚╝╩ ╩ ╩╩ ╩╩═╝  ╚═╝ ╩ ╩ ╩ ╩ ╚═╝
  data: {
    // Main syncing/loading state for this page.
    syncing: false,

    // Form data
    formData: { /* … */ },

    // For tracking client-side validation errors in our form.
    // > Has property set to `true` for each invalid property in `formData`.
    formErrors: { /* … */ },

    // Server error state for the form
    cloudError: '',
  },

  //  ╦  ╦╔═╗╔═╗╔═╗╦ ╦╔═╗╦  ╔═╗
  //  ║  ║╠╣ ║╣ ║  ╚╦╝║  ║  ║╣
  //  ╩═╝╩╚  ╚═╝╚═╝ ╩ ╚═╝╩═╝╚═╝
  beforeMount: function() {
    // Attach raw data exposed by the server.
    _.extend(this, SAILS_LOCALS);
  },
  mounted: async function() {
    //…
  },

  //  ╦╔╗╔╔╦╗╔═╗╦═╗╔═╗╔═╗╔╦╗╦╔═╗╔╗╔╔═╗
  //  ║║║║ ║ ║╣ ╠╦╝╠═╣║   ║ ║║ ║║║║╚═╗
  //  ╩╝╚╝ ╩ ╚═╝╩╚═╩ ╩╚═╝ ╩ ╩╚═╝╝╚╝╚═╝
  methods: {

    handleParsingForm: function() {
      var argins = this.formData;

      return argins;
    },

    submittedForm: async function() {
      // Executed after submission.
    },

  }
});

<button type="submit" class="btn" v-on:click="setValue(someValue)">Submit</button>

  methods: {

    setValue: function (someValue) {
      this.formData.someValue = someValue;
    },

}