ECMA standardized js only some of the recent capacity, and there are no standard to use when writing a js massive project if you are using a modular development.
CommonJS regulate how when we want to develop large-scale program to develop modular time, as well as modular when the communication of different files.
CommonJS specification: Links
CommonJS javaScript language customization for a module specification, programming API Specification
node.js followed Commonjs specification