Sending An Event From A Workflow
# Sending an event to other workflows
The this.select function is used to target other workflows and send them an event from the handle or onEvent generator functions.
For exemple:
module.exports.handle = function* (...) {
...
this.select.workflow().withId("<id>").send("<event name>", ...<event data>);
...
};
The ability to communicate between workflows with events is a very powerful feature that allow sophisticated behavior - such as synchronization between workflows (eg. see sequential workflows)
# Sending an event to itself
As a shortcut, a workflow can directly send an event to itself with:
module.exports.handle = function* (...) {
...
this.send("<event name>", ...<event data>);
...
};
Below, we use this to wait for 3 different events (3 documents to be received) before continuing:
module.exports.handle = function* (...) {
...
if (this.allDocReceived !== true) {
yield this.wait.event("allDocsReceived").forever();
}
...
}
module.exports.onEvent = function* (eventName, ...eventData) {
if (eventName === "doc1Received") {
this.doc1Received = true;
}
if (eventName === "doc2Received") {
this.doc2Received = true;
}
if (eventName === "doc3Received") {
this.doc3Received = true;
}
if (this.this.doc1Received && this.doc2Received && this.doc3Received) {
this.allDocReceived = true;
this.send("allDocsReceived");
}
}