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Aggregate: Carry

Sample-and-hold memory cell. When a value arrives on write, it is stored AND emitted on result. When a value arrives on trigger (without a write), the most recently held value is re-emitted (or the configured Default value on the very first trigger).

Useful inside iterator bodies to carry a constant or a previously-computed value across iterations. The held value is type-checked against Value type — mismatched writes fail the step.

Example
write=7  →  result=7
trigger  →  result=7
write=11 →  result=11
trigger  →  result=11

Parameters​

Value type—REQUIRED

Wire type the carry holds (String, Number, JSON, …). Determines both the type accepted on write and the type emitted on result.

Default value

Value emitted on the first trigger call before anything has been written. When omitted, a trigger-only call before any write fails with a missing-connector error.

Input​

Write

New value to store and emit. Must match the configured Value type.

Trigger

Re-emit the last held value (any value type — only its arrival matters).

Output​

Result

The value that was just written, or the most recently held value when only trigger fired.