cycle-contrib.ts

export function mix<
  COMB extends {
    [CS in keyof ComponentSinks]?: (arg: {
      [K in keyof COMPONENTS]: Stream<any>
    }) => ComponentSinks[CS]
  },
COMPONENTS extends {
  [COMPNAME in keyof COMPONENTS]: {
    [SINKNAME in keyof ComponentSinks]?: (COMB[SINKNAME] extends (arg: infer STREAMS) => any ? (
      COMPNAME extends keyof STREAMS ? STREAMS[COMPNAME] : ComponentSinks[SINKNAME]
    ) : ComponentSinks[SINKNAME])
  }
}
  >(componentSinks: COMPONENTS, combines?: COMB): Partial<ComponentSinks>{
    // Get all unique keys present in the array of sinks
    const keys = _.flow([
      _.values,
      o => _.map(o, _.keys),
      _.flatten,
      _.uniq
    ])(componentSinks)

    // array of arrays containing key & mixed sinks, or each key
    const arrys = _.map(keys, key => {
      // get object of sinks for the key containing undefineds in the right places
      const streams = _.flow([
        sinks => _.map(sinks, (sink, component) => [component, sink[key]]),
        _.fromPairs
      ])(componentSinks)

      const mixed$ = doCombine(combines, key, streams)

      const memoryMixed$ = key == "Layout" ?
        mixed$.remember()
        :
        mixed$

      return [key, mixed$]
    })

    //  Create an object with keys as keys and values as merged streams
    return _.fromPairs(arrys)
  }