Context

To make it easy to pass state between functions responding to a request, Yggdrasil Server packages the original request, normalized parameters, options, your app's context, utilities, and more in a single, shared YggdrasilServerContext object (commonly named ygg).

Some Yggdrasil Server features (Yggdrasil Server Router and Conduit) have their own state that they provide to you via an extended version of the YggdrasilServerContext. This extended version uses prototype-based inheritance so that methods implemented in the original object continue to run there.

To make it so that you don't have to pass ygg into every function you call, and to ensure the correct context (base/extended) is being referenced, built-in functions that live in the ygg context object uses the this keyword to access the context. Additionally, functions that you add as top-level members to your app's context object will be appropriately bound so that they can access the context through this (the Conduit server client requires this).

Please observe the following practices to avoid inadvertently breaking Yggdrasil Server's context:

Accessing context

Always use the ygg variable passed to you, if provided to you by Yggdrasil Server. While you can and should pass the ygg variable to your own helper functions, you should not use the base context object from a Conduit handler, for example (the Conduit context provided by Yggdrasil Server should be used instead). Additionally, do not store the ygg variable outside or beyond the scope of a request.

Calling context-based functions

Always access context functions and members directly through the context object. Do not store them in another variable, or the this context will be broken. For example, do throw ygg.status(400, "NOT_FOUND") instead of const status = ygg.status; throw status(400, "NOT_FOUND");. Furthermore, do not use .bind, .apply, or anything else that changes the this context.

Using your own context-based functions

Any top-level member functions present in your app context will be automatically bound to the appropriate context, so you can use this inside them to access the context without requiring a separate ygg parameter. Please note that this strategy is intended only for accessing whatever context is available. If you specifically need a Conduit context, for example, it is recommended to use an explicit ygg parameter to enforce that.