projectdoc.doctype.requirement.auto-id-pattern:
 {
    "specs": [
        {
            "doctypes": [],
            "parentProperty": "ID Prefix",
            "function": {
                "format": "5",
                "increment": 10
            }
        }
    ]
  }

The example above applies to requirement documents that are added to any parent document (doctypes is empty, otherwise the parent doctype identifiers that select this specification would be listed).

The parentProperty that defines the prefix is named "ID Prefix". If this property is not found, the Prefix "ID" would be used as default. So whenever a new requirement document is created, it will check if there are already siblings, and if not, use the given prefix and the following number format to create the auto-incremented identifier.

The function defines the formatting rules. In format the digit defines the number of digits of a number block. In the example these are 5. If the number has less than five digits, it will be filled with zeros. The increment shows the next number. In the example this is a ten-numbers step. If later a requirement needs to be added between to existing requirements, there is at least some space.

If the document that references all major requirements, has an "ID Prefix" property with the value "REQ", then the generated identifier for the first requirements document will be "REQ-00010", the next will be "REQ-00020", and so forth. The first subrequirement of the second requirement will have the ID "REQ-00020-00010".

projectdoc.doctype.requirement.auto-id-pattern: {}

projectdoc.doctype.requirement.auto-id-pattern:
 {
    "specs": [
        {
            "doctypes": [docsection],
            "function": {
                "format": "4",
                "increment": 100
            }
        },
        {
            "doctypes": [],
            "function": {
                "format": "10",
                "increment": 10
            }
        }
    ]
  }

The above example shows that the requirement documents on the first level, which are attached to a document of type docsection, have another increment block format than requirements that are attached to a document of any other type. This includes the requirement doctype itself. In other words: sub requirements have a space of 10 digits, while the root requirements have only four.