const fromIter = require('callbag-from-iter');
const iterate = require('callbag-iterate');
 
const source = fromIter([10, 20, 30, 40]);
 
iterate(x => console.log(x))(source);   // 10
                                        // 20
                                        // 30
                                        // 40

const fromIter = require('callbag-from-iter');
const iterate = require('callbag-iterate');
 
const source = fromIter([10, 20, 30, 40].entries());
 
iterate(x => console.log(x))(source); // [0,10]
                                      // [1,20]
                                      // [2,30]
                                      // [3,40]