Skip to main content

Triggers

You can have one query trigger another query.

Triggered queries can bypass access control rules, so this comes in handy when updating one collection owned by a user and another collection not owned by the same person.

For example, a user likes a tweet, which triggers an increment of the like count that the user doesn't have access to update.

You can think of it as an equivalent to Firestore Triggers. It's an essential component when building apps.

Add Triggers​

  • key : name of the trigger
  • on : create | update | delete
  • func : FPJSON logic

FPJSON will get an object containing the data before and after the change.

{
  data: { before, after, id, setter }
}

A trigger to increment the like count.

const { expect } = require("chai")

const trigger = {
  key: "inc-count",
  on: "create",
  func: [["upsert", [{ count: db.inc(1) }, "like-counts", { var: "data.id" }]]]
}
await db.addTrigger(trigger, "likes")

// like tweet
await db.set({ data: Date.now(), user: "Bob" }, "likes", "abc")

// like-count has been incremented
expect((await db.get("like-counts", "abc")).count).to.equal(1)

Remove Triggers​

Specify the trigger key to remove.

await db.removeTrigger("inc-count", "like-counts")