fluture/src/both.js

FantasyLand compliant (monadic) alternative to Promises

import {createParallelTransformation, earlyCrash, earlyReject} from './internal/parallel.js';
import {noop} from './internal/utils.js';
import {createTransformation, Resolve, application1, application, future} from './future.js';

export var PairTransformation = createTransformation(1, 'pair', {
  resolved: function PairTransformation$resolved(x){
    return new Resolve(this.context, [x, this.$1]);
  }
});

export var BothTransformation =
createParallelTransformation('both', earlyCrash, earlyReject, noop, {
  resolved: function BothTransformation$resolved(x){
    return this.$1._transform(new PairTransformation(this.context, x));
  }
});

export function both(left){
  var context1 = application1(both, future, arguments);
  return function both(right){
    var context2 = application(2, both, future, arguments, context1);
    return right._transform(new BothTransformation(context2, left));
  };
}