HI, > 1) how much slower is === than == (and similarly !== vs !=) in AS and JS?
In AS I don’t know but in JS in most browsers it’s in general 5-20% faster but does vary in what you are comparing. > I seem to recall that certain types and values did a lot of implicit > coercions in "==" and "!=“. Yep and this can cause other issues as well. [1] == and != are often referred to as the evil twins. This in particular should give cause for alarm. [2] This for instance “ \n\n\n” == 0 is true! Tools like JSLint and SonarCube encourage === and !== to be used. Most coding guidelines also prefer === and !==. [3] > 2) How much slower and fatter is initializing properties to null? Given it’s a one off and a comparison is likely to be made several time I would assume the cost of setting to null would be a lot lower. > IIRC, in ActionScript, unless you are using "*", all other types cannot > have the value undefined, so most code never needed to worry about the > difference. The vast majority of regular Flex SDK code just uses "==" and > "!=“. There’s a few edge cases that you do need to be concerned i.e. empty and not so empty strings that equate to false rather than true. > For "*", I believe we are emitting ES5 and/or only supporting browsers > that run ES5, so I think that means that undefined cannot be redefined and > (typeof Foo === 'undefined') isn't necessary. That’s my understanding as well. Thanks, Justin 1. https://stackoverflow.com/questions/359494/which-equals-operator-vs-should-be-used-in-javascript-comparisons <https://stackoverflow.com/questions/359494/which-equals-operator-vs-should-be-used-in-javascript-comparisons> 2. http://dorey.github.io/JavaScript-Equality-Table/ <http://dorey.github.io/JavaScript-Equality-Table/> 3. http://javascript.crockford.com/code.html <http://javascript.crockford.com/code.html>
