Big game for Liverpool!! Come on #Simple… fast… better for screen reading.
February 24th, 2011 by Stewart Matheson
The other day I needed an array that tracked its current position so I can use methods like previous and next. I wrote a simple container to do this. Here is the code.
function EnhancedArray(a) { if(typeOf(a) != "array") throw("Did not get an array"); var counter = 0; var internalArray = a; this.next = function(){ counter++; if(counter > (internalArray.length -1)) { counter = 0; } return internalArray[counter]; } this.previous = function(){ counter--; if(counter < 0) { counter = (internalArray.length - 1); } return internalArray[counter]; } this.current = function(){ return internalArray[counter]; } }
Some of you may have noticed that I am using “typeOf” and not “typeof”. This is because Javascripts existing “typeof” function is broken. Douglas Crockford explains typeof better than I can and also provides a fix. Here is the fix.
function typeOf(value) { var s = typeof value; if (s === 'object') { if (value) { if (value instanceof Array) { s = 'array'; } } else { s = 'null'; } } return s; }
No we are set to use our new Enhanced Array. We can do the following
var testArray = ["apple", "mango", "pineapple", "banana", "cherry", "grape", "kiwi"], a = new EnhancedArray(testArray); a.current(); //apple a.next(); //mango a.previous(); //apple a.previous(); //kiwi
Handy if you need to track the current location of an array. Enhanced array even goes around the corner both ways. Here is the test code.
$(document).ready(function(){ module("enhanced_array"); var testArray = ["apple", "mango", "pineapple", "banana", "cherry", "grape", "kiwi"], a; test("Array should be able to be created", function(){ a = new EnhancedArray(testArray); ok(a); }); test("Counter is a zero when the enhanced array is created", function(){ equals(a.current(), "apple"); }); test("Counter returns the next item in the array", function(){ equals(a.next(), "mango"); equals(a.next(), "pineapple"); equals(a.next(), "banana"); equals(a.next(), "cherry"); equals(a.next(), "grape"); equals(a.next(), "kiwi"); }); test("Test next to come to the start of the array", function(){ equals(a.next(), "apple"); }); test("Test prevrious goes to the back of the array", function(){ equals(a.previous(), "kiwi"); equals(a.previous(), "grape"); }); test("current works after counter has been moved", function(){ equals(a.current(), "grape"); }); });
September 9th, 2010 by Stewart Matheson
I have updated the assert random gem to v 0.4.0. I started this update a few weeks ago but had one silly problem. I had the same problem in a different project solved it today and then applied it to assert-random. Feels good to finally get this update out the door. The update allows users to set the amount of iterations that assert random will use. Handy. You can install the gem in the usual way.
gem install assert-random
There is doc in the readme that can be viewed here.
September 5th, 2010 by Stewart Matheson
Telescope is a new type of forum application. Why not check the information page?