xls-loader v1.1.3

If webpack version >= 5 go to use excels-loader

npm install --save-dev xls-loader

webpack.config.js

module.exports = {
  module: {
    rules: [
            {
                test: /\.xls.?$/,
                use: {
                    loader: 'xls-loader'
                }
            }
        ]
    }
}