callbag-map

/**
* callbag-map
* -----------
*
* Callbag operator that applies a transformation on data passing through it.
* Works on either pullable or listenable sources.
*
* npm install callbag-map
*
* Example:
*
* const fromIter = require('callbag-from-iter');
* const iterate = require('callbag-iterate');
* const map = require('callbag-map');
*
const source = map(x => x 0.1)(fromIter([10,20,30,40]));
*
* iterate(x => console.log(x))(source); // 1
* // 2
* // 3
* // 4
*/

const map = f => source => (start, sink) => {
if (start !== 0) return;
source(0, (t, d) => {
sink(t, t === 1 ? f(d) : d)
});
};

module.exports = map;