Check if an array of objects contains a certain key-value in JavaScript
The other day, I was stumbled upon a scenario where I need to check whether there exists at least one key of a certain value in an array of objects.
Check the following for example.
const products = [
{
id: 1,
name: "Cereal",
category: "food"
},
{
id: 2,
name: "Shampoo",
category: "grocery"
},
{
id: 3,
name: "Fruit jam",
category: "food"
}
];
As you can tell, we have an array of objects called products and now let’s say, we want to check if this array has at least one object that has category set as “grocery”.
Turns out, it’s pretty easy to check this using the Array.prototype.some() method.
The some() method to the rescue
Quoting from MDN,
The some() method tests whether at least one element in the array passes the test implemented by the provided function. It returns true if, in the array, it finds an element for which the provided function returns true; otherwise it returns false. It doesn’t modify the array.
So, if we want to check if the products array has at least one object that has category set as “grocery”, we can do it through the some() method like so.
const hasGrocery = products.some(function(product) {
return product.category === 'grocery';
})
console.log(hasGrocery);
// outputs: true
As you can tell, the some() method accepts a callback as its argument from which we can return the condition. Based on the truthiness of this condition, the some() method will return true or false.
In our example, it will return true since the array contains an object that has category set as “grocery”. And that’s exactly what I wanted to check!
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