fifo-array

A fixed-length, first-in-first-out array for Javascript.

Install

npm install fifo-array

-or-

npm install ben-bradley/fifo-array

Methods

All FifoArray methods behave exactly like the Array.prototype methods, but they trim the array down to have a length equal to the max. Which end of the array that is trimmed is the difference:

• FifoArray.push() - Trims from the front of the array until length === max.
• FifoArray.unshift() - Trims from the back of the array until length === max.
• FifoArray.splice() - Trims from the back of the array until length === max.

All other Array.prototype methods are untouched and will behave as expected. I couldn't find any other methods that could add elements to the FifoArray

Examples

Basic usage

var FifoArray = require('fifo-array');
 
var fifoArray = new FifoArray(3, [ 'a', 'b', 'c', 'd' ]);
console.log(fifoArray); // => [ 'b', 'c', 'd' ]
console.log('max:', fifoArray.max); // => max: 3
fifoArray.push(1, 2);
console.log(fifoArray); // => [ 'd', 1, 2 ]

#push()

var fifoArray = new FifoArray(3);
fifoArray.push(2, 3, 4, 5);
console.log(fifoArray); // => [ 3, 4, 5 ]

#unshift()

var fifoArray = new FifoArray(3, [ 0, 1, 2 ]);
fifoArray.unshift('a', 'b');
console.log(fifoArray); // => [ 'a', 'b', 0 ]

#splice()

var fifoArray = new FifoArray(3, [ 0, 1, 2 ]);
fifoArray.splice(1, 2, 'a'); // at position 1, remove 2 elements and add 'a'
console.log(fifoArray); // => [ 0, 'a' ]
 
fifoArray.splice(1, 0, 'b'); // at posotion 1, remove 0 elements and add 'b'
console.log(fifoArray); // => [ 0, 'b', 'a' ]

.max

// if necessary, it chops the array down to the new max
var fifoArray = new FifoArray(5, [ 0, 1, 2, 3, 4 ]);
console.log(fifoArray); // => [ 0, 1, 2, 3, 4 ]
fifoArray.max = 3;
console.log('new max:', fifoArray.max); // => new max: 3
console.log(fifoArray); // => [ 0, 1, 2 ]
 
fifoArray.max = 10;
fifoArray.push('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h');
console.log(fifoArray); // => [ 1, 2, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h' ]

Version History

• 0.1.2 - Added readme.md bling
• 0.1.1 - Initial release
• 0.0.* - Internal development

References

Here are several sources that helped me write this module:

• http://www.bennadel.com/blog/2308-creating-a-fixed-length-queue-in-javascript-using-arrays.htm
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty
• https://variadic.me/posts/2013-10-22-bind-call-and-apply-in-javascript.html