Object.keys
I adore JavaScript objects. Love them. You're probably asking "well, why don't you marry them?" Trust me: if I could, I would. Arrays are nice and all but object keys provide another level of structure and information that is invaluable. For example, it's much faster search an object for a key than it is to search an array for value presence.
The way we've always iterated on an Object instance was always a for loops with a hasOwnProperty check which was ugly; Object.keys (not Object.prototype.keys) provides an array of Object properties!
var person = {
firstName: 'David',
lastName: 'Walsh',
// ...
};
Object.keys(person).forEach(function(trait) {
console.log('Person ', trait,': ', person[trait]);
});
If you work with JSON or simply raw JavaScript objects, and you haven't been using Object.keys, now is the time to ditch the old method for this elegant solution!
![Create Namespaced Classes with MooTools]()
MooTools has always gotten a bit of grief for not inherently using and standardizing namespaced-based JavaScript classes like the Dojo Toolkit does. Many developers create their classes as globals which is generally frowned up. I mostly disagree with that stance, but each to their own. In any event...
![Write Better JavaScript with Promises]()
You've probably heard the talk around the water cooler about how promises are the future. All of the cool kids are using them, but you don't see what makes them so special. Can't you just use a callback? What's the big deal? In this article, we'll...
![Using MooTools to Instruct Google Analytics to Track Outbound Links]()
Google Analytics provides a wealth of information about who's coming to your website. One of the most important statistics the service provides is the referrer statistic -- you've gotta know who's sending people to your website, right? What about where you send others though?
![Duplicate the jQuery Homepage Tooltips Using MooTools]()
The jQuery homepage has a pretty suave tooltip-like effect as seen below:
Here's how to accomplish this same effect using MooTools.
The XHTML
The above XHTML was taken directly from the jQuery homepage -- no changes.
The CSS
The above CSS has been slightly modified to match the CSS rules already...
Why don’t you use this:
for (let trait in person){console.log(trait)}@Franz,
for..in iterating over NON own properties.
Not very well supported http://caniuse.com/#feat=let
Obligatory https://babeljs.io/
Also would iterate over prototype properties.
The
for each...instatement is deprecated as the part of ECMA-357 (E4X) standard. E4X support has been removed, butfor each...inwill not be disabled and removed because of backward compatibility considerations. Consider usingfor...ofinstead. (Please refer to bug 791343.)Also: Use
const, not let. The loop creates a new context in each iteration, the loop variable therefore is constant unless your loop-code changes it.