robojones/once

import { PromiseEmitter } from './PromiseEmitter'

/**
 * Creates a new promise for an event.
 * @param target The EventEmitter that will emit the event.
 * @param event The name of the event.
 * @param arrayMode If set to true the promise will resolve to an array containing all arguments of the event.
 */
export function createPromise(target: PromiseEmitter, event: string, arrayMode: boolean): Promise<any> {
    return new Promise((resolve, reject) => {
        target.once(event, (...args) => {

            // remove from cache
            delete target.__promises__[event]

            if (event === 'error') {
                reject(args[0])
            } else if (arrayMode) {
                resolve(args)
            } else {
                resolve(args[0])
            }
        })
    })
}