brotherton-erpnext/erpnext/selling/page/point_of_sale/pos_number_pad.js

erpnext.PointOfSale.NumberPad = class {
    constructor({ wrapper, events, cols, keys, css_classes, fieldnames_map }) {
        this.wrapper = wrapper;
        this.events = events;
        this.cols = cols;
        this.keys = keys;
        this.css_classes = css_classes || [];
        this.fieldnames = fieldnames_map || {};

        this.init_component();
    }

    init_component() {
        this.prepare_dom();
        this.bind_events();
    }

    prepare_dom() {
        const { cols, keys, css_classes, fieldnames } = this;

        function get_keys() {
           return keys.reduce((a, row, i) => {
               return a + row.reduce((a2, number, j) => {
                   const class_to_append = css_classes && css_classes[i] ? css_classes[i][j] : '';
                   const fieldname = fieldnames && fieldnames[number] ? 
                       fieldnames[number] : 
                       typeof number === 'string' ? frappe.scrub(number) : number;
                   
                   return a2 + `<div class="numpad-btn pointer no-select rounded ${class_to_append}
                                       flex items-center justify-center h-16 text-md border-grey border" data-button-value="${fieldname}">${number}</div>`
               }, '')
           }, '');
       }

        this.wrapper.html(
            `<div class="grid grid-cols-${cols} gap-4">
                ${get_keys()}
           </div>`
        )
    }

    bind_events() {
       const me = this;
       this.wrapper.on('click', '.numpad-btn', function() {
           const $btn = $(this);
           me.events.numpad_event($btn);
       })
    }
}