customMethods.js

const customMethods = {
  install(Vue) {
    // INSTALL
    if (this.installed) return;
    this.installed = true;

    Vue.options = Vue.util.mergeOptions(Vue.options, {
      created: function() {
        if (this.$options.customMethod) {
          // If found in the component.
          this.$options.customMethod(); // Execute the customMethod.
        }
      },
    });
  },
};

export default customMethods;