Introduction
In JavaScript, we may wish to loop through an object. In this post, we'll look at how to do it.
How to loop through a JavaScript object?
To loop through a JavaScript object we can use several methods such as: Object.keys(obj)
, for...of
, Object.entries()
or for...of
.
To iterate over object properties we can use Object.keys()
combined with and Array.prototype.forEach()
method
const obj = {
name: 'John',
surname: 'Doe'
};
Object.keys(obj).forEach(function(key) {
console.log(key, obj[key]);
});
To loop through an Object in JavaScript we can use for...of
introduced in ECMAScript 6
const obj = {
name: 'John',
surname: 'Doe'
};
for (const key of Object.keys(obj)) {
console.log(key, obj[key]);
}
Iterating over an Object's properties could be achieved with Object.entries()
method from ECMAScript 8
const obj = {
name: 'John',
surname: 'Doe'
};
Object.entries(obj).forEach(
([key, value]) => console.log(key, value)
);
The for...of
loop combined with destructuring, and Object.entries
:
const obj = {
name: 'John',
surname: 'Doe'
};
for (const [key, value] of Object.entries(obj)) {
console.log(key, value);
}
There is also an old fashioned way to iterate over an object in JavaScript
var obj = {
name: 'John',
surname: 'Doe'
};
for (var key in obj) {
if (obj.hasOwnProperty(key)) {
console.log(key + " -> " + obj[key]);
}
}
Conclusion
In this article, we learned how to loop through a JavaScript object. As you can see there are several methods to do it, you can choose the best that fits your needs.
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