LoopIterator

Let's you run through an array and go back to the beginning when you run too far. You can also iterate backwards and keep a history.

Installation

npm install loop-iterator --save

Usage

var LoopIterator = require('loop-iterator');

var iterator = new LoopIterator(['Ina', 'Sebastian', 'Henner']);
console.log(iterator.current()); // 'Ina'
console.log(iterator.next()); // 'Sebastian'
console.log(iterator.next()); // 'Henner'
console.log(iterator.next()); // 'Ina'
console.log(iterator.prev()); // 'Henner'

Set the index to whichever value you want and the iterator stays in the allowed range by circulating.

var LoopIterator = require('loop-iterator');

var iterator = new LoopIterator(['Ina', 'Sebastian', 'Henner']);
console.log(iterator.currentIndex()); // 0
console.log(iterator.currentIndex(4)); // 1
console.log(iterator.currentIndex(-1)); // 2
console.log(iterator.currentIndex(3)); // 0

var counter = 0;
setInterval(function(){
	iterator.currentIndex(counter); //0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2...
	iterator.current(); //'Ina', 'Sebastian', 'Henner', 'Ina', 'Sebastian', 'Henner'...
	counter++;
}, 1000);

If you want to use the history add a second parameter with the number of items you want to record to the constructor.

var LoopIterator = require('loop-iterator');

var iterator = new LoopIterator(['Ina', 'Sebastian', 'Henner'], 2);
console.log(iterator.next()); // 'Sebastian'
console.log(iterator.next()); // 'Henner'
console.log(iterator.next()); // 'Ina'
console.log(iterator.history(1)); // 'Henner', you can also write history() instead
console.log(iterator.history(2)); // 'Sebastian'
console.log(iterator.history(3)); // undefined, history not long enough

Instead of require you can also just use a good old script tag.

<script src="loop-iterator.js"/>

Documentation

Constructor:

LoopIterator(array [, history])

• array - The array you want to iterate over.
• history - Optional. The number of elements you want to keep in the history.

Methods:

• current() : Returns the current element.
• next() : Iterates to the next element and returns it.
• prev() : Iterates to the previous element and returns it.
• currentIndex([index]) : Returns or sets the current index.
• nextIndex() : Iterates to the next element and returns the index.
• prevIndex() : Iterates to the previous element and returns the index.
• history(level) : Returns the n'th element in history. level defaults to 1.
• historyIndex(level) : Returns the n'th index in history. level defaults to 1.

Release History

• 0.3.1 Fixes bug when accessing history before there is any history.
• 0.3.0 Added circulation functionality when setting the index
• 0.2.0 Optimizations
• 0.1.0 Initial release

License

Copyright 2015 Henner Wöhler. Licensed under the MIT license.