Delay by One

Delays a stream by one tick. Emits a configured initial value first, then on every input tick emits the value seen on the previous tick.

How it fits

{{type:t}} -> {{component:delay_by_one}} -> {{type:t}} (previous-tick value, with the configured initial emitted first)

Typical backends

• Diff against previous frame: source -> {{component:delay_by_one}} paired with the live stream -> {{component:pack_tuple}} -> {{component:evaluate_expression}} (delta).
• Edge detection on booleans: {{type:Bool}} -> {{component:delay_by_one}} paired with the current value -> {{component:evaluate_expression}} (xor) -> trigger downstream.
• Rate-of-change on counters: counter -> {{component:delay_by_one}} -> {{component:evaluate_expression}} comparing live vs delayed.
• Hold-last fallback: detection stream -> {{component:delay_by_one}} -> {{component:select_stream}} switching between live and held value.

Caveats

• Holds exactly one tick of memory. Longer histories require chaining or a stateful worker.
• The configured initial value is emitted once at startup and never again, even after a runtime restart of the surrounding deployment.
• Output cadence matches input cadence one-to-one; the worker stalls if the upstream stalls.