The Number.isInteger() method in JavaScript is useful for checking whether a number is a whole number or not.

Syntax:

Number.isInteger(value);

Parameters:

• value: The value to be checked.

Return Value:

It returns a boolean value,i.e. either true or false. It will return true if the passed value is of the type Number and an integer, it returns false. 

Example 1: This example checks for some values if they are integers or not using the Number.isInteger() method in JavaScript.

console.log(Number.isInteger(-2));
console.log(Number.isInteger(0));
console.log(Number.isInteger(2));   

Example 2: Here, a negative number is passed as an argument. This code logs `false` because `-2.56` is not an integer. `Number.isInteger()` returns `false` for non-integer numeric values.

console.log(Number.isInteger(-2.56));    

Example 3: Here, a string is passed as an argument. This code logs "Output : false" because "hi" is not a number and Number.isInteger() returns false for non-numeric values.

console.log("Output : " + Number.isInteger("hi"));