Details in JavaScript Array Methods with Examples

 

Why we need JavaScript array methods.

JavaScript arrays are data structures that allow you to store multiple values in a single variable. JavaScript arrays are commonly used to hold lists of data such as numbers, strings, objects, or other arrays.

We need JavaScript array methods because they allow us to perform various operations on arrays easily and efficiently. These methods can help us to add or remove elements from an array, sort an array, filter an array, create a new array from an existing array, and more. By using these methods, we can write more concise and readable code, which can save time and reduce the likelihood of errors.

Most uncommon array methods with examples

More or less, we use JavaScript array methods now a days, but most are the common once. We are actually not so much aware others important methods. Today I am trying to introduce those and definitely sure this will be helpful to write more concise and readable code than you before did.

1.Array.from()

Array.from() method creates a new array from an array-like object or inerrable object.

Example:

const str = 'hello';

const arr = Array.from(str);

console.log(arr); // ["h", "e", "l", "l", "o"]

2.Array.of()

Array.of() method creates a new array with a variable number of arguments.

Example:

const arr = Array.of(1, 2, 3, 4, 5);

console.log(arr); // [1, 2, 3, 4, 5]

3.Array.findIndex()

Array.findIndex() method returns the index of the first element in the array that satisfies the provided testing function.

Example:

const arr = [2, 4, 6, 8, 10];

const index = arr.findIndex(num => num > 5);

console.log(index); // 2

4.Array.fill()

Array.fill() method fills all the elements of an array from a start index to an end index with a static value.

Example:

const arr = [1, 2, 3, 4, 5];

arr.fill(0, 2, 4);

console.log(arr); // [1, 2, 0, 0, 5]

5.Array.flatMap()

Array.flatMap() method first maps each element using a mapping function, then flattens the result into a new array.

Example:

const arr = [1, 2, 3, 4, 5];

const result = arr.flatMap(num => [num * 2]);

console.log(result); // [2, 4, 6, 8, 10]

6.Array.some()

Array.some() method tests whether at least one element in the array passes the test implemented by the provided function.

Example:

const arr = [1, 2, 3, 4, 5];

const result = arr.some(num => num > 3);

console.log(result); // true

7.Array.every()

Array.every() method tests whether all elements in the array pass the test implemented by the provided function.

Example:

const arr = [1, 2, 3, 4, 5];

const result = arr.every(num => num > 3);

console.log(result); // false

8.Array.reduceRight()

Array.reduceRight() method applies a function against an accumulator and each value of the array (from right-to-left) to reduce it to a single value.

Example:

const arr = [1, 2, 3, 4, 5];

const result = arr.reduceRight((acc, num) => acc + num);

console.log(result); // 15

9.Array.keys()

Array.keys() method returns an iterator over the keys (indices) of the array.

Example:

const arr = ['a', 'b', 'c', 'd', 'e'];

const iterator = arr.keys();

for (const key of iterator) {

  console.log(key); // 0, 1, 2, 3, 4

}

10.Array.values()

Array.values() method returns an iterator over the values of the array.

Example:

const arr = ['a', 'b', 'c', 'd', 'e'];

const iterator = arr.values();

for (const value of iterator) {

  console.log(value); // "a", "b", "c", "d", "e"

}

When we should not use JavaScript array methods

While JavaScript array methods can be very useful for manipulating arrays, there are situations where you might want to avoid using them. Here are a few scenarios where using JavaScript array methods may not be the best approach:

Large arrays: 

When working with very large arrays, some array methods (such as sort) can be very slow and memory-intensive. In these cases, it may be more efficient to use a different approach, such as iterating over the array using a for loop.

Performance-critical applications: 

If you're building a high-performance application that needs to process large amounts of data quickly, you may need to use lower-level programming techniques to optimize performance. In these cases, using JavaScript array methods may not be the best option.

Compatibility issues: 

Some older browsers and versions of JavaScript may not support all of the array methods available in newer versions. If you need to support older browsers, you may need to use alternative approaches to manipulate arrays.

Functional limitations: 

Some array methods may not be able to handle certain types of data or may not provide the level of control you need for a particular task. In these cases, you may need to use more advanced data structures or custom algorithms to achieve your desired result.


If you like the post please like, comment and shares. Also, you can give suggestions and your thoughts.
---------------------------------------------------------------------------------------------------------------------------