for-next

simple for loop iterator thing

Simple example

const $for = require("for-next");

$for(["cat", "dog", "dingo"], (animal, {next}) => {

  console.log("animal: ", animal);
  // The iterator won't continue if you don't invoke next().
  // the object specified can have a value property
  // which the iterator collects all values to output when resolved.
  next({value: {isCat: animal === "cat"}})

// The interval is the amount of time in milliseconds
// to wait per iteration. If you set this to 0 (or don't specify),
// the iterator won't use setTimeout (so be careful of stackoverflows)
}, {interval: 500})
  .then(values => {

    const cats = values.filter(animal => animal.isCat);
    console.log("Cats: ", cats.length);

  })
;

More examples

const countdown = 5;
$for(countdown, (index, {index, next, stop, values, ctx}) => {

  let count = countdown - index + 1;

  if(count <= 3){
    if(ctx.counted){
      count -= .5;
      next({value: count});
    }else{
      // You can skip forward/backward
      next({skip: -1, value: count});
      // The ctx variable is the context scoped to individual iterations (AND skipped iterations).
      // For example, if you skip to another iteration, it will pull the current context with it.
      ctx.counted =  true;
    }
  }else{
    next({value: count});
  }

  console.log(count);

}, {interval: 1000})
  .then(values => {
    console.log("Go!");
    console.log({values});
  })
;
/* OUTPUT */
// 5
// 4
// 3
// 2.5
// 2
// 1.5
// 1
// Go!
// { values: [ 5, 4, 3, 2.5, 2, 1.5, 1 ] }

More examples work in progress..