Polling Triggers

Polling triggers allow you to poll for new events by periodically fetching records and comparing them with previously fetched records.

Example#

async function fetchAllUsers() {
  // fetch and return list of all Users from oldest to newest
  // this should be an array of objects with `id` property
}

const allUsers = await fetchAllUsers();

// compute new id snapshot
const newIdSnapshot = new Set(allUsers.map((a) => a.id));

// determine new Users added since previous snapshot
const newUserIds = utils.diffIdSnapshot(newIdSnapshot, context.prevIdSnapshot);

// events is an array of objects of the Trigger Payload shape
const events = allUsers
  .filter((a) => newUserIds.has(a.id))
  .map((a) => utils.flattenTriggerPayload(a));

return {
  newIdSnapshot,
  events,
};

Polling execution context#

Claim	Type	Description
`prevIdSnapshot`	`Set<string>`	The set of polled IDs returned from previous poll
`authData`	`object`	The object holding the auth data from JWT / OAuth

Polling execution return value#

Claim	Type	Description
`nextIdSnapshot`	`Set<string>`	The set of polled IDs in this poll
`events`	`object[]`	An array of new events - objects of the Trigger Payload shape.