Javascript 如何在Web包中定义全局变量？

我对webpack不熟悉

正在尝试使用webpack进行生成。一切正常，没有错误，但当我尝试在浏览器中启动代码时，它会显示：

build.js:118未捕获引用错误：未定义outputValues at countinteger（build.js:118） 在模块上。（build.js:104） 在网页上需要（build.js:20） 在build.js:84 在build.js:87

那么，如何在webpack中定义全局变量呢

//index.js

(() => {
'use strict';})();

const outputValues = document.querySelectorAll('.output-values')[0];
const countButton = document.querySelectorAll('.count-button')[0];
const resetButton = document.querySelectorAll('.reset-button-disabled')[0];

import { countIntegers } from './button.js';

const counter = countIntegers();

countButton.addEventListener('click', counter.showNextInteger);
resetButton.addEventListener('click', counter.reset);

//button.js

export const countIntegers = () => {
  let currentInteger = 0;
    outputValues.innerText = currentInteger;
      return {
        showNextInteger: () => {
         if(currentInteger + 1 > 0) {
           resetButton.style.cursor = 'pointer';
           resetButton.disabled = false;
           resetButton.className = 'reset-button-enabled';
          }
            return outputValues.innerText = ++currentInteger;
        },
        reset: () => {
          outputValues.innerText = 0;
          resetButton.style.cursor = 'default';
          resetButton.disabled = true;
          resetButton.className = 'reset-button-disabled';
            return currentInteger = 0;
        }
      };
}

//webpack.config

const path = require('path');

module.exports = {

    entry: './assets/output/scripts/index.js',

    mode: 'none',

    output: {
        filename: 'build.js',
        path: path.join(__dirname, "/assets/bundle")
    }
};

谢谢你的帮助