cyclejs-test-helpers/src/index.ts

A small collection of useful utilities

import xs from 'xstream';
import { mockTimeSource, MockTimeSource } from '@cycle/time';

export { diagramArbitrary } from './diagramArbitrary';
export { undefinedOr } from './undefinedOr';

export function promise(run : (err: any) => void) : Promise<boolean>
{
    return new Promise((resolve, reject) => run(err => err ? reject(err) : resolve(true)));
}

export function withTime(test : (Time : MockTimeSource) => void): () => Promise<boolean> {
    return function() {
        const Time = mockTimeSource();

        test(Time);

        return promise(Time.run);
    }
}

export function addPrevState(main : any, prevState : any, stateName: string = 'state'): any {
    return function(sources : any) : any {
        const initReducer = xs.of(() => prevState);
        const appSinks = main(sources);
        return {
            ...appSinks,
            [stateName]: xs.merge(initReducer, appSinks[stateName] || xs.never())
        };
    };
}