Require statement error on importing modules from TestRunner.html - mocha.js

Question

I am new to mocha. My scripts below works when i run from the terminal. However, there is no result when i run from testrunner.html. On checking, it seems to be because of var xl = require('./excel');. if i comment this statement, it works. How can i make this work? i need to import custom modules for my script.
Updated test.js to incorporate RequireJS
Post changes: works on browser and termial
module1.js
if(typeof define !== 'undefined')
{
define([], function() {
return {
get: function() {
return get();
}
};
});
}
else if(typeof exports !== 'undefined') {
module.exports = {
get: function(){
return get();
}
};
}
function get(){
return "hello node world";
}
test.js
if(typeof requirejs == 'undefined') {var requirejs = require('requirejs');}
if(typeof chai == 'undefined') {var chai = require('chai');}
requirejs.config({
baseUrl: '.',
paths: {
},
nodeRequire: require
});
describe("RequireTest()", function(){
var module1;
before(function(done){
requirejs(['./module1'],
function(_module) {
console.log('before fired');
module1 = _module;
if(typeof requirejs == 'undefined') {mocha.run();}
done();
});
});
it('test case: ', function(){
console.log(module1.get());
chai.expect(1+1).to.equal(2);
});
});
testrunner.html (snippet)
<div id="mocha"></div>
<script src="../node_modules/mocha/mocha.js"></script>
<script src="../node_modules/chai/chai.js"></script>
<script src="../node_modules/requirejs/require.js"></script>
<script>mocha.setup('bdd')</script>
<script src="./test.js"></script>
<script>mocha.run();</script>

Answer 1

When you run Mocha at the command line you are using Node.js, which provides require.
When you run it in the browser, there is no require that the browser provides. You need to use a module loader at run-time like RequireJS or SystemJS. Or you need to use a packager like Webpack or Browserify that will process your code beforehand and turn it into a single bundle that incorporates all your code.
Note that whether third-party modules you use can be loaded in a browser, is a determination you have to make module-by-module. If you use a module that uses Node's child_process module to spawn a new process, for instance, you won't be able to just use that module in the browser because browsers don't provide child_process.