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Step Up Your JS: A Comprehensive Guide to Intermediate JavaScript

Object.keys

Explore how to use Object.keys to convert object keys into arrays for easy manipulation with methods like map, filter, and reduce. Learn to chain these methods to process object data efficiently and solve practical problems with a single method chain.

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Like arrays, JavaScript objects have several functions available to them. There’s one that is by far more useful than any of the others: Object.keys.

One way to loop through each of an object’s properties is to use a for-in loop. This will iterate through the properties and allow us to work with the object’s keys.

Javascript (babel-node)
const obj = {
    val1: 'abc',
    val2: 'def'
};
for(const key in obj) { // const works here, but not in normal for-loops
    console.log(key, obj[key]);
}
// -> val1 abc
// -> val2 def

Object.keys allows us to do more. It takes in an object as a parameter and returns an array that contains the keys of the object.

Javascript (babel-node)
const obj = {
    val1: 'abc',
    val2: 'def'
};
const keys = Object.keys(obj);
console.log(keys); // -> ['val1', 'val2]

That’s really all there is to this function. ...