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.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();

   }
}

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