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
• fn : FPJSON logic
• fields : fields to match (match anything if not specified)
• match : all | any | none (default to any)

If fields is specified, the fn is triggered only the fields are changed with the specified match type.

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

let vars = { before, after, db, dir, doc, owner, signer, signer23, ts, ts64 }

A trigger to increment the like count.

const { expect } = require("chai")
 
const trigger = {
  key: "inc_likes",
  on: "create",
  fn: [["update", [{ likes: { _$: ["inc"] }, "notes", "$after.object"]]],
  fields: [ "object" ]
  match: "any"
}
await db.addTrigger(trigger, "likes")
 
// like a note
await db.set("add:like", { object: noteId }, "likes")
 
// likes has been incremented
assert.equal((await db.get("notes", noteId)).likes, 1)

Get Triggers

const triggers = (await db.stat("likes")).triggers ?? {}

Remove Triggers

Specify the trigger key to remove.

await db.removeTrigger({ key: "inc_likes" }, "likes")