In Ext JS, each compilation unit (usually a class, but Jangaroo allows global variables, constants or functions to also be compilation units) has a fully-qualified name that is globally unique. Ext JS uses this name to reference other compilation units when importing them. The name consists of a (hierarchical, dot-separated) namespace and the local name of the compilation unit.

Ext JS organizes compilation units in packages. A package has a name and can have a namespace, which is used as a prefix for all fully-qualified names of its compilation units. The package name and namespace prefix need not to be the same identifier.

As TypeScript is an extension of ECMAScript, it uses the ECMAScript module system. Since ES5, any source file that contains imports and/or exports is a module. In import directives, modules are references by file path without extension. This file path may either be relative to the current source file, starting with ./ or ../, or it refers to an npm package name and then specifies the relative path within that package.