Array Methods

These are the few array methods that I had issues working with while starting out my javascript journey. Let’s quickly look at them and see how to effectively use them in development.

As the name implies, it is used to check if it includes an element in an array. This method returns TRUE if the element is included and returns FALSE if otherwise. This javascript method is case sensitive.
Let’s look at how it works;
Syntax: array.includes(element, start).
Now, we see that this method takes in two parameters; the first is the element we are checking for, while the second parameter is the position at which the array should start the search.
Example 1:
const arr = [ Red, Orange, Black, Purple, Grey];
const check = arr.includes(Red, 0);
Result: true
Example 2:
const arr = [Red, Blue, Green, Grey];
const check = arr.includes(blue, 1);
Result: false
The second example returns false because the blue in our array started with capital letter B.
Example 3:
const arr = [Pear, Banana, Apple, Orange, Mango];
const check = arr.includes(Pear, 3);
Result: false
This example returns false because we are checking if the array contains Pear starting from position 3.

This method test if all the element in an array pass a particular test implemented by a provided function. The every() executes the function once for all the array elements. every() returns false for any element that fails the test at any point without checking other values and returns TRUE if all the elements pass the test.
Example 1 :
function isBigEnough (x){
return x≥50
}
const arr = [20, 40,90,42,55];
const check = arr.every(isBigEnough);
Result: false

The fill() method fills the specified element in an array with a static value. We must specify the starting and ending position, else it will fill every element in the array. This method overwrites the original array.
Syntax: array.fill(value, start, end)
Example 1:
const fruits = [apple, pear, orange, mango];
const check = fruit.fill(banana, 1, 3);
Result: [apple, banana, banana, banana]

The filter method creates a new array with all the elements that pass the test implemented by the provided function. If no element pass the test, an empty array will be returned.
Example 1:
const age = [30, 40, 39, 10, 65, 27, 72];
const check = age.filter(ages => ages ≤ 40);
Result: [30,40,49,10,27];

The concat() method is used to merge two or more arrays. It does not change the existing array but returns a new array containing the values of the joined arrays.

The shift() method removes the first element of an array.
This method changes the length of the original array.
Example:
const check=[a, b, c,d e,f ];
check.shift();
Result: [b,c,d,e,f];

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