Some of the docs specify the type for properties, while others do not. A good first contribution would be to update the properties that are missing this information. As an example, look at https://nodejs.org/api/process.html#process_process_connected vs. https://nodejs.org/api/child_process.html#child_process_child_connected. These two things represent the same concept, but the one in the child_process docs have the data type.