is string integer javascript code example
Example 1: Javascript string to int
var myInt = parseInt("10.256"); //10
var myFloat = parseFloat("10.256"); //10.256
Example 2: javascript check if number
function isNumber(n) { return /^-?[\d.]+(?:e-?\d+)?$/.test(n); }
------------------------
isNumber('123'); // true
isNumber('123abc'); // false
isNumber(5); // true
isNumber('q345'); // false
isNumber(null); // false
isNumber(undefined); // false
isNumber(false); // false
isNumber(' '); // false
Example 3: js check if string is integer
function isInt(str) {
return !isNaN(str) && Number.isInteger(parseFloat(str));
}
Example 4: javascript pareseint
parseInt(string, radix);
console.log(parseInt(' 0xF', 16));
// expected output: 1500
console.log(parseInt('321', 2));
// expected output: 0
console.log(parseInt('321', 10));
// expected output: 321
/*
* @param string Required. The value to parse. If this argument is not
* a string, then it is converted to one using the ToString abstract
* operation. Leading whitespace in this argument is ignored.
*
* radix
* @param radix Optional. An integer between 2 and 36 that represents
* the radix (the base in mathematical numeral systems) of the string.
* Be careful—this does not default to 10!
* @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt#Description
* for what happens when radix is not provided
*/
Example 5: how to check if a string is an integer javascript
isNaN(num) // returns true if the variable does NOT contain a valid number