What this snippet does
Module augmentation allows extending types defined in other modules without modifying the original source code.
Expected output
30
Why practise typing this
Typing modules & namespaces code builds muscle memory for the symbols and indentation TypeScript uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.
More TypeScript practice
- Exporting and importing a typed variableModules & Namespaces · intermediate
- Exporting an interface and implementationModules & Namespaces · intermediate
- Importing a type without 'type' modifier in isolatedModulesModules & Namespaces · intermediate
- Defining a default exportModules & Namespaces · intermediate
- Default exporting a class instanceModules & Namespaces · intermediate
- Mixing default and named imports incorrectlyModules & Namespaces · intermediate