Exceution of simple Javascript in Rails app doesn’t work

I am new to this topic and online resources didnt help. I am trying to set up a simple button which onClick executes something in JavaScript. I wanted to implement on the front-end to add html to the DOM. It seems I am doing something wrong with regards to referencing the programmed JS Code.

  1. I modified my application.js to add require("./invoices/invoice_positions"):

    // present in this directory. You're encouraged to place your actual application logic in
// a relevant structure within app/javascript and only use these pack files to reference
// that code so it'll be compiled.

require("@rails/ujs").start()
require("turbolinks").start()
require("@rails/activestorage").start()
require("popper.js")
require("bootstrap")
require("jquery")
require("inputmask")
require("channels")
require('./nested_forms/addFields')
require('./nested_forms/removeFields')

require("./invoices/form")
require("./invoices/select")
require("./payments/form")
require("./header_menu")
require("./invoices/invoice_positions")
// Uncomment to copy all static images under ../images to the output folder and reference
// them with the image_pack_tag helper in views (e.g <%= image_pack_tag 'rails.png' %>)
// or the `imagePath` JavaScript helper below.
//
// const images = require.context('../images', true)
// const imagePath = (name) => images(name, true)

  2. I added the function under app/javascript/invoices/invoice_positions.js with some dummy code:

function increaseInvoicePositions() {window.alert("BAM");}
  1. I added this to my view because of some online help:
<%= content_for :head do %>
  <%= javascript_include_tag "/invoices/invoice_positions" %>
<% end %>
  1. I added this button to the view:
<%= button_tag t('invoice_positions.increase'), type: "button", onclick: "increaseInvoicePositions()", class: "btn btn-secondary" %>

Result

In theory after reloading the page I assume it works but it fails with a browser error in Chrome. I restarted the server but it didnt help. What am I missing?
JS Error