gossamer/worker_parent
Helpers a worker script uses to communicate with its parent thread. Import this from your worker module to send and receive messages without runtime-specific code.
Pair with gossamer/worker on the parent side.
Sending Gleam values
Values cross via structured-clone and arrive on the parent side as
Dynamic. See gossamer/message_port for
what round-trips cleanly and how to decode the received data.
Transferring ports
A MessagePort reachable from the data
passed to post_message is automatically detached
on this side and re-attached on the parent — the message and any
ports ride a single atomic call. Transferred ports are no longer
usable on the sender. To extract a transferred port from the
received Dynamic, use
message_port.from_dynamic.
Values
pub fn post_message(data: a) -> Result(Nil, Nil)Sends data back to the parent thread. Any
MessagePort reachable from data is
detached on this side and arrives on the parent at its position in
the data structure. Returns an error if data can’t be serialized
by the structured-clone algorithm — functions, symbols, and most
class instances are not cloneable. Equivalent to JavaScript’s
self.postMessage inside a Worker (or parentPort.postMessage
inside node:worker_threads).
pub fn set_on_message(handler: fn(dynamic.Dynamic) -> a) -> NilRegisters a handler invoked for each message the parent sends.
Decode the payload with gleam/dynamic/decode; extract any
transferred ports with
message_port.from_dynamic.
ArrayBuffer payloads are wrapped as BitArray; other values pass
through unchanged. Equivalent to JavaScript’s self.onmessage
inside a Worker (or parentPort.onmessage inside
node:worker_threads).