undo3d-run-test/runner/hub.mjs

A collection of utilities for testing Undo3D, and apps built with Undo3D

//// Receives and broadcasts events. Helps keep things loosely coupled.




//// CLASS

export default class Hub {

    ////
    constructor () {

        //// Define `handlerArrays` - an object where each key is an event-name,
        //// and each value is an array of handlers.
        this.handlerArrays = {}
    }

    //// Registers a new handler, under one or more event-names. Similar to
    //// the DOM’s `addEventListener()`.
    on (eventName, handler) {
        const parts = eventName.split(' ')
        if (1 < parts.length) { // go recursive for space-delimited event-names
            parts.map( part => this.on(part, handler) )
        } else { // create a handler-array if none currently exists
            this.handlerArrays[eventName] = this.handlerArrays[eventName] || []
            this.handlerArrays[eventName].push(handler)
        }
    }

    //// Triggers the handlers for an event-name or sequence of event-names. The
    //// event-name, along with all other arguments, will be passed as arguments
    //// to each handler.
    fire (eventNames, ...payload) {
        eventNames = eventNames.split(' ').map( eventName => eventName.trim() )
        for (const eventName of eventNames) {
            const handlerArray = this.handlerArrays[eventName]
            if (! handlerArray) continue // no such handler-array
            handlerArray.map( //@TODO capture and return all results?
                handler => handler.apply( null, [eventName].concat(payload) )
            )
        }
    }
}