Handler<T, U> (type)

Every time attach*, waitFor or pipe is invoked a new Handler<T, U> is attached to the Evt<T>.
Handlers can be listed using the evt.getHandler() method.
type Handler<T,U> = {
​
    //Method for detaching the handler from the Evt, returns false if 
    //if invoked when the handler is no longer attached.
    detach(): boolean;
​
    //The promise returned by the attach*() and waitFor() method.
    promise: Promise<U>;
​
​
    /* Properties that depends on the method used to attach the handler */
​
    //true if the handler was attached using a method containing "prepend"
    //in it's name. Example: evt.$attachOncePrepend(...)
    prepend: boolean;
​
    //... if the method contained "extract"
    extract: boolean;
​
    //... if the method contained "once"
    once: boolean;
​
    //if the method was waitFor()
    async: boolean;
​
​
​
    /* Properties passed as argument to the method used to attach the handler */
​
    //Default: ()=> true, a filter that matches all events.
    op: Operator<T,U>; 
​
    //Default: undefined
    ctx?: Ctx; 
​
    //Default: undefined.
    timeout?: number;
​
    //Undefined only when the handler was attached using evt.waitFor()
    callback?: (transformedData: U)=> void;
​
};
Glossary relative to handers:
An event is said to be matched by a handler if posting it causes the callback to be invoked. In practice this is the case when the handler's operator returns true or [ value, ].
An event is said to be handled by a handler if the event data is matched or if posting it causes the handler and/or other potential handlers to be detached. In practice this is the case when the handler's operator returns "DETACH" or {DETACH: Ctx}. It is possible to test if a given event data is handled by at least one of the handlers attached to an Evt<T> by using the evt.isHandled(data) method.
Helper types
React hooks
Last modified 4mo ago