method to check if integer javascript code example

Example 1: javascript check if number

function isNumber(n) { return /^-?[\d.]+(?:e-?\d+)?$/.test(n); } 

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isNumber('123'); // true  
isNumber('123abc'); // false  
isNumber(5); // true  
isNumber('q345'); // false
isNumber(null); // false
isNumber(undefined); // false
isNumber(false); // false
isNumber('   '); // false

Example 2: js is variable int

// The === operator is used for checking
// the value and the type of a variable

var data = 1;

if (data === parseInt(data, 10))
    alert("data is integer")
else
    alert("data is not an integer")