---
id: SCH-10
family: GR-SCHEMA
level: core
profiles: [storage-api, editor-client]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-schema/sch-10
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# SCH-10 — The map from a schema type to a port lane

*GR-SCHEMA (Part I) · level: core · profiles: storage-api, editor-client · added in 1.0*

A port's lane is what an editor colours it by and what it checks a wire against. It is derived from the property's schema type by one closed map.

## The rule

> **Normative.** This is the rule.
>
> 1. A property's schema type maps to exactly one lane: `string` to `string`; `number` and `integer` to `number`; `boolean` to `boolean`; `array` to `array`; `object` to `json`; `null` to the sink.
>
> 2. Any other value, and an absent type, yield the sink, never `string`.
>
> 3. A property's `x-data-type` overrides the mapped lane whenever it names a lane the served port configuration declares; any other value is ignored and the schema type maps as usual.
>
> 4. Every lane this derivation can return, override included, must also be declared by the served port configuration: an undeclared lane leaves the port compatible with nothing an editor can draw.

## Related rules

- Names: SCH-34, SCH-35, SCH-36, SCH-37, SCH-41
- Referenced by: SCH-8, SCH-10.a, SCH-34, SCH-35, SCH-41

---

Rule identifiers are permanent and are never renumbered. This specification carries
no implementation status: each implementation publishes its own standing against
these rules. Licensed CC BY 4.0.