To empty an array in JavaScript, we can use the array literal. We can directly assign an empty array literal to the variable, it will automatically remove all the elements and make the array empty.

1. Empty Array using Array Literal

We can empty the array using the empty array literal syntax.

Syntax

arr = [ ];

// Given array 
let a = [ 10, 20, 30, 40, 50 ];

// Assign new array to make it empty
a = [];

// Display the updated array
console.log("Updated Array: ", a)

Updated Array:  []

2. Using array.length Property

The JavaScript array.length property is used to set or return the length of the array.

Syntax

arr.length  = 0;

// Given array
let a = [ 10, 20, 30, 40, 50 ];

// Empty the array by setting its length to 0
a.length = 0;

// Display Updated array and its length
console.log("Updated Array: ", a);
console.log("Length of Updated Array: ", a.length);

Updated Array:  []
Length of Updated Array:  0

3. Using array.splice() Method

The JavaScript array.splice() method is used to remove elements from certain index and add new elements to the array.

Syntax

arr.splice(0);   

It will start removing elements from 0 index and as the number of elements is not given it will remove all elements present in the array.

// Given array 
let a = [ 10, 20, 30, 40, 50 ];

// Remove elements using array.splice() method
a.splice(0);

// Display the updated array
console.log("Updated Array: ", a)

Updated Array:  []

4. Using array.pop() Method

The JavaScript array.pop() method is used to remove the elements one by one from the array.

Syntax

arr.pop();

// Given array 
let a = [ 10, 20, 30, 40, 50 ];

// While loop to iterate 
while( a.length > 0){
	
    // Remove the last element in
    // each iteration
	a.pop()
}

// Display the updated array
console.log("Updated Array: ", a)

Updated Array:  []

Note: Array clearing techniques in JavaScript is essential for effective data management.