how to check if string is valid integer javascript code example

Example 1: javascript check if a value is an int

// The Number.isInteger() checks to see if the passed value is an integer
// Returns true or false

Number.isInteger(2); //True
Number.isInteger(90); //True
Number.isInteger("37"); //False
Number.isInteger(false); //false

Example 2: how to check if a string is an integer javascript

isNaN(num)         // returns true if the variable does NOT contain a valid number