What is a Safe Integer? 
A safe integer is an integer that has the following properties 

• A number that can be represented as an IEEE-754 double precision number i.e. all integers from (2⁵³ - 1) to -(2⁵³ - 1)).

What is an IEEE-754 double-precision number? 
Double-precision floating-point format is a computer number format, which occupies 64 bits in computer memory. It represents a wide range of numeric values by using a floating-point.

The IEEE 754 standard specifies a binary64 as having:

• Sign bit: 1 bit 
• Exponent: 11 bits 
• Significant precision: 53 bits (52 explicitly stored) 

isSafeInteger() Method In JavaScript: The isSafeInteger() method in JavaScript is used to check whether a number is a safe integer or not.

Syntax:  

Number.isSafeInteger(Value)

Parameters: 

• Value: It is the number to be checked for safeinteger() method.

Return Value: The toExponential() method in JavaScript returns true if the value is a safe integer Number, else it returns false.

Below are examples of the Number isSafeInteger() Method. 

Example 1: This example uses the safeinteger() method to check if 4 is a safe integer or not.

console.log("Output : " + Number.isSafeInteger(44));

Output : true

Example 2: Passing a positive number as an argument in the isSafeInteger() method.

console.log("Output : " + Number.isSafeInteger(23));

Output : true

Example 3: Passing a negative number as an argument in the isSafeInteger() method.

console.log("Output : " + Number.isSafeInteger(-23));

Output : true

Example 4: Passing a number(with decimals) as an argument in the isSafeInteger() method.

console.log("Output : " + Number.isSafeInteger(0.5));

Output : false

Example 5: Passing an equation( which equates to an infinite value) as an argument in the isSafeInteger() method.

console.log("Output : " + Number.isSafeInteger(0 / 0));

Output : false

Code Explanation: JavaScript uses double-precision floating-point format numbers as specified in IEEE 754 and can only safely represent numbers between -(2⁵³ - 1) and 2⁵³ - 1. If the parameter passed lies in this specified range then the number.isSafeInteger() method returns true else false.

We have a complete list of Javascript Number Methods, to check those please go through the Javascript Number Complete Reference article.

Supported Browsers:  

• Google Chrome 34 and above
• Firefox 32 and above
• Apple Safari 10 and above
• Opera 21 and above
• Edge 12 and above