Hooks

trigger

type	methods	multi	details
before, after, around	create, patch, update, remove	yes	source

Options

The options of the trigger hook are of type: Subcription or Subcription[] or (context: HookContext) => Promisable<Subscription | Subscription[]>. But what is a Subcription?

A subscription is an object with the following properties:

Property	Description
service	The service to subscribe to. To be used if you share trigger options between several services/methods. Type: string | string[] optional - Default: undefined
method	The method to subscribe to. To be used if you share trigger options between several services/methods. Type: string | string[] optional - Default: undefined
data	Check the context.data for something. Uses sift.js under the hood. On multi create, every item of context.data is checked on its own, just like on single create: the action only runs for the created items whose data matched. An item is mapped to the result by its id in context.data, otherwise by its position in context.result. Type: Record<string, any> | boolean | (item: T, context: HookContext) => Promisable<boolean | Record<string, any>> optional - Default: true
result	Check the context.result for something. Uses sift.js under the hood. Type: Record<string, any> | boolean | (change: { item: T; before: T | undefined }, context: HookContext) => Promisable<boolean | Record<string, any>> optional - Default: true
params	Check the context.params for something. Uses sift.js under the hood. Type: Record<string, any> | boolean | (item: T, context: HookContext) => Promisable<boolean | Record<string, any>> optional - Default: true
fetchBefore	The trigger hook lets you compare the result against the item before. This is disabled by default for performance reasons. If you use before, it will fetch the items in the before hook automatically. If you don't need before but your result looks something like: ({ before }) => ({ publishedAt: { $gt: before.publishedAt } }) you need to set fetchBefore:true explicitely As a function, it's called once per service call in the before hook, so context.result isn't available yet. Type: boolean | (context: HookContext) => Promisable<boolean> optional - Default: false
before	Check the before object from trigger before hook, if available. Uses sift.js under the hood. Type: Record<string, any> | boolean | (item: T, context: HookContext) => Promisable<boolean | Record<string, any>> optional - Default: true
manipulateParams	You can extend the params for the subscription, e.g. for population. The items after the call are refetched by their id, so params.query doesn't have the filters of the call there. Query params your adapter needs to shape the items, like $eager, have to be added to params.query again. The query of the call is still in context.params.query. Type: (params: Params, context: HookContext) => (Promisable<Params>) optional - Default: undefined
action	The action, that will be run, if all checks pass for the subscription. Type: ({ before, item }, { context, items, subscription }) => Promisable<any> Type (batchMode=true): (changes: [change: { before, item }, options: { context, items, subscription }][], context) => Promisable<any> optional - Default: undefined
batchMode	Enables batch mode. In batch mode: If multiple items are passed to create, it will only run action once with all items matching the conditions. Type: boolean optional - Default: false
isBlocking	Whether the trigger hook should wait for the async action before continuing. As a function, it's called once per service call in the before hook, so context.result isn't available yet. Type: boolean | (context: HookContext) => Promisable<boolean> optional - Default: true
debug	Logs why the subscription runs or gets skipped, prefixed with [FEATHERS_TRIGGER DEBUG]. Helpful if an action doesn't run as expected. As a function, it's called once per service call in the before hook, so context.result isn't available yet. Type: boolean | (context: HookContext) => Promisable<boolean> optional - Default: false

Action

The action from subscription is the function that runs, after all conditions are fulfilled. The function looks like the following:

const action = async ({ before, item }, { context, items, subscription }) => {
  // do your own implementation
};

// In batch mode

const action = async (changes) => {
  for (const [{ before, item }, { context, items, subscription }] of changes) {
    // do your own implementation
  }
};

changesById

type	methods	multi	details
before, after, around	create, patch, update, remove	yes	source

Options

Property	Description
params	With the params options, you can manipulate params for changesById if you need to, e.g. for population. The items after the call are refetched by their id, so params.query doesn't have the filters of the call there. Query params your adapter needs to shape the items, like $eager, have to be added to params.query again. The query of the call is still in context.params.query. Type: (params: Params, context: HookContext) => (Params | Promise<Params>) optional - Default: undefined
skipHooks	Use find or _find for refetching Type: boolean optional - Default: false