JavaScript Rules

This morning while commuting to the office, reading JavaScript for Web Developers, I bumped into a question: how could I improve a well known algorithm that gets the smallest or the largest number in an array by using built-in Math methods such as Math.min and Math.max. For those not familiar with these methods, they return the smallest or the largest number respectively from a list of zero or more numbers passed as parameters, e.g.: Math.min(4,3,9,6) returns 3, Math.max(4,3,9,6) returns 9. I was wondering if calling such methods using apply and an Array as argument would work. I could hardly wait to get to the office to test it out on my Firebug console. I first tried:

Math.max.apply(Math, [4,8,3,5,1,2]);

And bingo! It works!

Continue reading ‘Fast min/max in arrays’ »

I’ve just finished chapter 7: Writing Efficient JavaScript by Nicholas Zakas on Steve Souders‘ new book, Even Faster Web Sites, where he presents several string optimization techniques to improve JavaScript performance and wondered which algorithm does String.indexOf method implements on JavaScript engines (aka ECMAScript engines).
A few months ago I’ve asked this question to Yahoo! fellow Douglas Crockford and he said the ECMAScript standard does not require a specific algorithm, so it could vary with each browser. You can check that on section 15.5.4.7 of Standard ECMA-262. I decided then to download the most popular open-source JavaScript engines source codes and found mainly 3 algorithms:

Continue reading ‘String searching algorithms in JavaScript engines’ »