Each file is considered an "external" module. The use of the module keyword creates an internal module, and was used before the ECMAScript 2015 addition of namespaces for the same purpose. Now that namespace is available, the use of module is deprecated because it does the same thing, and its use could confuse maintainers unaware of the history of the language.

Noncompliant Code Example

module myMod {  // Noncompliant
  // ...
}

Compliant Solution

namespace myMod {
  // ...
}