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inject

Sends one message with a fixed payload each time you click its ▶ icon while the editor is connected to the board.

Properties

  • payload type — bool, number or string. Default bool. The output's type follows it, so the editor checks the wire against the input it feeds (see Wiring).
  • value — the value to send, read as the payload type (see Typed values). Default true.

Wiring

Input — none. inject is a source.

Output — a message with payload set to the value and topic set to an empty string.

Behavior

The ▶ icon and the rest of the node are separate click targets. The ▶ fires the node. A click anywhere else on the node opens its property panel, connected or not.

Each click sends one message. inject never fires on its own, neither on a schedule nor when the flow starts, so a flow whose only sources are inject nodes does nothing until you click one. To send a message when the flow starts, use startup. To send one repeatedly, use timer.

Errors

  • The editor isn't connected. The console shows [inject: connect to a device first -- clicking only fires while live] and nothing is sent.
  • The value isn't a number, with payload type number. The deploy goes through; the click fails on the board with a [NODE_ERROR] naming this node and inject value 'abc' is not a valid number. See Reading a node error.
  • A node error in this node's chain stops the chain. See Reading a node error.