require fs-js in browser does not work after creating and including Bundle

[gintares]

package
https://www.npmjs.com/package/fs-js?activeTab=code

I downloaded source and map from :
https://cdn.jsdelivr.net/npm/fs-js@1.0.6/index.min.js
https://cdn.jsdelivr.net/sm/371e7d4afc5f7cd968f336bfe709890d019ca103eb9566a6ff3639d97efcefe0.map

I used browserify to create bundle
$ browserify -r fs-js ./fs.min.js > fsbund.js

in browser there is window on-load function to load all files, i.e. istart test.js when everything is loaded:

<script type="text/javascript" src="/js/fs.min.js"></script> <script type="text/javascript" src="/js/fsbund.js"></script> <script type="text/javascript" src="/js/test.js"></script>

I am getting error,

Uncaught ReferenceError: require is not defined
    at jsdelivr-header.js:1:1

where said contains this content:

/**
 * Minified by jsDelivr using UglifyJS v3.0.24.
 * Original file: /npm/fs-js@1.0.6/index.js
 * 
 * Do NOT use SRI with dynamically generated files! More information: https://www.jsdelivr.com/using-sri-with-dynamic-files
 */

test.js

var fs = require('fs-js'); 
var ckpdf = fs.open('/js/browserjs_test.txt', 'r', (err,fd) => {
    console.log(fd);
}); 

source, fs.min.js

var fs=require("fs");module.exports=fs;
//# sourceMappingURL=fs.js.map

map, fs.js.map

{"version":3,"sources":["jsdelivr-header.js","/npm/fs-js@1.0.6/index.js"],"names":[],"mappings":"AAAA;AACA;AACA;AACA;AACA;AACA;AACA,ACNA,IAAI,GAAK,QAAQ,MAEjB,OAAO,QAAU","file":"/npm/fs-js@1.0.6/index.js","sourceRoot":"","sourcesContent":["/**\n * Minified by jsDelivr using UglifyJS v3.0.24.\n * Original file: /npm/fs-js@1.0.6/index.js\n * \n * Do NOT use SRI with dynamically generated files! More information: https://www.jsdelivr.com/using-sri-with-dynamic-files\n */\n","var fs = require('fs');\r\n\r\nmodule.exports = fs;"]}

[ljharb]

fs can't work in the browser, because there's no filesystem there.