Edit Page

`.initialize(cb)`

The initialize feature allows a hook to perform startup tasks that may be asynchronous or rely on other hooks. All Sails configuration is guaranteed to be completed before a hook’s initialize function runs. Examples of tasks that you may want to put in initialize are:

Logging in to a remote API
Reading from a database that will be used by hook methods
Loading support files from a user-configured directory
Waiting for another hook to load first

Like all hook features, initialize is optional and can be left out of your hook definition. If implemented, initialize takes one argument: a callback function which must be called in order for Sails to finish loading:

initialize: function(cb) {

   // Do some stuff here to initialize hook
   // And then call `cb` to continue
   return cb();

}

Hook timeout settings

By default, hooks have ten seconds to complete their initialize function and call cb before Sails throws an error. That timeout can be configured by setting the _hookTimeout key to the number of milliseconds that Sails should wait. This can be done in the hook’s defaults:

defaults: {
   __configKey__: {
      _hookTimeout: 20000 // wait 20 seconds before timing out
   }
}

Hook events and dependencies

When a hook successfully initializes, it emits an event with the following name:

hook:<hook name>:loaded

For example:

The core orm hook emits hook:orm:loaded after its initialization is complete.
A hook installed into node_modules/sails-hook-foo emits hook:foo:loaded by default
The same sails-hook-foo hook, with sails.config.installedHooks['sails-hook-foo'].name set to bar would emit hook:bar:loaded
A hook installed into node_modules/mygreathook would emit hook:mygreathook:loaded
A hook installed into api/hooks/mygreathook would also emit hook:mygreathook:loaded

You can use the "hook loaded" events to make one hook dependent on another. To do so, simply wrap your hook’s initialize logic in a call to sails.on(). For example, to make your hook wait for the orm hook to load, you could make your initialize similar to the following:

initialize: function(cb) {

   sails.on('hook:orm:loaded', function() {

      // Finish initializing custom hook
      // Then call cb()
      return cb();

   });
}

To make a hook dependent on several others, gather the event names to wait for into an array and call sails.after:

initialize: function(cb) {

   var eventsToWaitFor = ['hook:orm:loaded', 'hook:mygreathook:loaded'];
   sails.after(eventsToWaitFor, function() {

      // Finish initializing custom hook
      // Then call cb()
      return cb();

   });
}

Is something missing?

If you notice something we've missed or could be improved on, please follow this link and submit a pull request to the sails-docs repo. Once we merge it, the changes will be reflected on the website the next time it is deployed.

Documentation

Concepts

Built with Love

The Sails framework is maintained by a web & mobile studio in Austin, TX, with the help of our contributors. We created Sails in 2012 to assist us on Node.js projects. Naturally we open-sourced it. We hope it makes your life a little bit easier!