in array how can we delete a particulary key javascript

Removing the Last Element of an Array

The pop() method removes and returns the last element of an array.

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

const x = myArray.pop();

console.log(`myArray values: ${myArray}`);
console.log(`variable x value: ${x}`);

Output:

myArray values: 1,2,3,4
variable x value: 5

Removing the First Element of an Array

The shift() method removes and returns the first element of an array.

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

const x = myArray.shift();

console.log(`myArray values: ${myArray}`);
console.log(`variable x value: ${x}`);

Output:

myArray values = 2,3,4,5
variable x value: 1

Removing an Element by Index

If you are identifying the item to be removed by its index, you can use the delete operator. If you want to use the value of the item you are removing, use the splice() method.

The delete Operator

The delete operator deletes the object property at the specified index, but does not update the length of the array, and the value at that index of the array will be undefined.

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

delete myArray[1];

console.log(`myArray values: ${myArray}`);

Output:

myArray values: 1,,3,4,5

The splice() Method

The splice() method takes two arguments, the index of the element you wish to remove and the index you wish to remove up to.

The splice() method creates a new array that stores all the values that were removed from the original array. The original array will no longer contain the values removed, and its length will be updated.

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

const x = myArray.splice(1, 1);

console.log(`myArray values: ${myArray}`);
console.log(`variable x value: ${x}`);

Output:

myArray values: 1,3,4,5
variable x value: 2

Removing an Element by Value

If you are identifying the element to be removed by its value, you can delete the element from its index after identifying the index with the indexOf() method. If you want to use the value of the element you are removing, then use the filter() method, or a combination of the indexOf() and splice() methods.

Combining indexOf() and splice() Methods

Pass the value of the element you wish to remove from your array into the indexOf() method to return the index of the element that matches that value in the array. Then make use of the splice() method to remove the element at the returned index.

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

const index = myArray.indexOf(2);

const x = myArray.splice(index, 1);

console.log(`myArray values: ${myArray}`);
console.log(`variable x value: ${x}`);

Output:

myArray values: 1,3,4,5
variable x value: 2

The indexOf() method returns the first index where the value matches the parameter passed into it, and -1 if no value is found to match.

The filter() Method

The array filter() method takes in a function as a required argument. The function requires one parameter currentValue, which represents the element in the array the filter() method is currently on while looping through the array.

The function should perform a check that returns true if the currentValue is the value of the element you wish to remove, and false if not.

The filter() method then returns an array that contains the values from the array that match the currentValue.

The values the filter() method returns are not removed from the original array, but that functionality can be added to the function you pass into filter().

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

function removeValue(value, index, arr) {
    // If the value at the current array index matches the specified value (2)
    if (value === 2) {
    // Removes the value from the original array
        arr.splice(index, 1);
        return true;
    }
    return false;
}

// Pass the removeValue function into the filter function to return the specified value
const x = myArray.filter(removeValue);

console.log(`myArray values: ${myArray}`);
console.log(`variable x value: ${x}`);

Output:

myArray values: 1,3,4,5 

variable x value: 2