Filter Node

Type: Function

Compatible with: Flow Graph, Connector Graph

Description:

The Filter Node selectively passes messages based on changes in the payload data. It caches incoming messages and emits them to the next node only when a specified value within the payload changes. This node is particularly useful for reducing redundant data transmission and focusing on relevant updates.

Settings Parameters:

• Mode:

  • Block Unless Value Changes: (Default) Emits a message only when any value within the payload changes from the previous message.
  • Block Unless Value is Greater (Number Only): Emits a message only when a specified numeric value within the payload increases compared to the previous message or a specified reference value.
  • Block Unless Value is Lower (Number Only): Emits a message only when a specified numeric value within the payload decreases compared to the previous message or a specified reference value.

• Property: The dot-notation path to the specific value within the msg object that you want to monitor for changes (e.g., msg.payload.temperature).

Input:

• msg: The message object whose payload will be filtered.

Output:

• msg: The filtered message object, emitted only when the specified value changes (according to the chosen mode).