A callbag listenable source that sends an initial number synchronously and then incrementally every x milliseconds.
npm install callbag-interval-immediate
const interval = require("callbag-interval-immediate");
const observe = require("callbag-observe");
const source = interval(1000);
observe(x => console.log(x))(source); // 0
console.log(0.5); // 0.5
// 1
// 2
// 3
// ...