Map contains key?
Description
Pure function returning true when the map has an entry under the given key. A null map contains nothing and returns false.
When to use
Use Map contains key? to check whether a map already has an entry for a given key before deciding what to do next — for example, branching between inserting a new record and updating an existing one. Because it is a pure generic node, it works with any map’s key and value types. A null map contains nothing and always returns false, so no null guard is needed before checking it.
Pins
Input pins
| Pin | Type | Default | Notes |
|---|---|---|---|
| Map | generic{generic} | — | The map to check. Key and value types resolve at design-time from the connected source. A null map contains nothing and always returns false. |
| Key | generic | — | The key to check for. Must match the map's key type. |
Output pins
| Pin | Type | Notes |
|---|---|---|
| Result | boolean | True when the map has an entry under the key, false otherwise — including when the map is null. |
Example
Before adding a newly seen ID to a deduplication map, check whether it is already present. Wire the map local variable into the Map input and the incoming ID into the Key input, then feed the Result output into a Branch’s Condition. The True execution output skips past Map put; the False output routes into Map put to record the ID.