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Object Keys, Values, and Entries: JavaScript ES6 Feature Series (Pt 9)
Finally, ECMAScript has introduced some much-needed object manipulation methods
Introduction
The inspiration for these pieces is simple: it’s the fact that there are still plenty of developers for whom JavaScript is sometimes completely confusing— or, at least, doesn’t always make a whole lot of sense.
But JavaScript still powers almost 95% of the 10 million most popular webpages, according to Wikipedia.
And since it only continues to increase in usage as time goes by, I wanted to provide a bunch of articles and examples of ES6+ features that I use regularly, for other developers to reference.
The aim is for these pieces to be short, in-depth explanations of various improvements to the language that I hope will inspire you to write some really cool stuff using JS. Who knows, you might even learn something new along the way.
This piece will focus on JavaScript objects and some handy new methods concerning keys, values, and the combination of the two that were standardized into the language in the last few years.
Object.keys()
This may sound hard to believe, especially if you’re coming from another programming language like Java, but up until ES2015, there was no built-in method in JavaScript to easily access an object’s property names, otherwise known as its keys.
Really?
Shocking, I know. Prior to this, a library like Lodash might be employed to do something that should be a basic, standardized method.
Happily, the ECMAScript committee got their act together with the release of ES2015, and the method Object.keys() was introduced. The method returns an array of a given object's own enumerable property names, in the same order as we get with a normal for loop.
Example of Object.keys() on an object:
const resistanceFighter = {
name: "John Connor",
age: 30,
title: "Resistance Leader",
fight() {
return `${this.name} leads the resistance fight against the machines.`
}
};console.log(Object.keys(resistan…
