Let’s see how we can quickly sort TypeScript / JavaScript object array by property.

We will sort the array in following ways:

• Sort the array by property in increasing order
• Sort the array by property in decreasing order

Consider following products array.

const products: Product[] = [
    { id: 1, name: 'Product 1', price: 100 },
    { id: 2, name: 'Product 2', price: 200 },
    { id: 3, name: 'Product 3', price: 300 },
    { id: 1, name: 'Product 1', price: 100 }
]

Sort the array by property in increasing order

Suppose we want to sort the array by price in increasing order.

We can use array sort method like following.

products.sort((prodA, prodB) => prodA.price > prodB.price ? 1 : -1);

console.table(products);

Output

Sort the array by property in decreasing order

Now let’s sort the products array by price in decreasing order.

products.sort((prodA, prodB) => prodA.price > prodB.price ? -1 : 1);

console.table(products);

Output

Array.prototype.sort()

Sort method sorts the elements of an array and returns the sorted array.

const months = ['March', 'Jan', 'Feb', 'Dec'];
months.sort();
console.log(months);
// expected output: Array ["Dec", "Feb", "Jan", "March"]

const array1 = [1, 30, 4, 21, 100000];
array1.sort();
console.log(array1);
// expected output: Array [1, 100000, 21, 30, 4]

References:

Array.prototype.sort()

Conclusion

In this post we learned how we can sort the object array by property in ascending and descending order.

Let’s see how we can efficiently remove the duplicates from the object array.

Consider the following products array.

const products: Product[] = [
    { id: 1, name: 'Product 1', price: 100 },
    { id: 2, name: 'Product 2', price: 200 },
    { id: 3, name: 'Product 3', price: 300 },
    { id: 1, name: 'Product 1', price: 100 }
]

This products array contains one duplicate product.

{ id: 1, name: 'Product 1', price: 100 }

We can remove the duplicates from object array using filter and findIndex array methods as following.

const prods = products.filter((value, index, array) => index == array.findIndex(item => item.id == value.id));

console.table(prods);

Output

Array.prototype.filter()

Filter method returns new array which passes the filter criteria.

const words = ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present'];

const result = words.filter(word => word.length > 6);

console.log(result);
// expected output: Array ["exuberant", "destruction", "present"]

Array.prototype.findIndex()

findIndex returns the index of the first element that satisfies the conditions, else returns -1.

const array1 = [5, 12, 8, 130, 44];

const isLargeNumber = (element) => element > 13;

console.log(array1.findIndex(isLargeNumber));
// expected output: 3

References:

Array.prototype.filter()

Array.prototype.findIndex()

Conclusion

In this post we learned how we can efficiently remove the duplicates from the object array.