Currently, the project does not seem to be using any "bundler" programs, these are programs that will take all of your files (for example your JavaScript files) and bundle them into a single output file.
During the bundling process, the output file will be optimised and altered, reducing the output code size and allowing the code to work on more devices.
Webpack is best for this as there is a tremendous amount of documentation and plugins available.
Currently, the project does not seem to be using any "bundler" programs, these are programs that will take all of your files (for example your JavaScript files) and bundle them into a single output file.
During the bundling process, the output file will be optimised and altered, reducing the output code size and allowing the code to work on more devices.
Webpack is best for this as there is a tremendous amount of documentation and plugins available.
Webpack: https://webpack.js.org/