index.js
function registerTarget(userId, channel, target, callback) {
    this.save(userId, channel, target, function (err) {
        // ensure that we're firing the callback asynchronously
        process.nextTick(callback, err)
    })

    // make it chainable
    return this
}
function registerTarget(userId, channel, target, callback) {
    this.save(userId, channel, target, function (err) {
        // ensure that we're firing the callback asynchronously
        process.nextTick(callback, err)
    })

    // make it chainable
    return this
}
function registerTarget ( userId , channel , target , callback ) { this . save ( userId , channel , target , function ( err ) { // ensure that we're firing the callback asynchronously process . nextTick ( callback , err ) } ) // make it chainable return this }
Register a new target of a channel.

@param {*} userId - User identifier. Type is mostly string or number but depends on the consumer.
@param {string} channel - Channel name.
@param {*} target - An address to send notifications to. Eg. phone number, email address, push notification token, etc.
@param {function} callback
@returns {Handover}
Register a new target of a channel .