Amiya Sahu Web Developer

Intresting Javascript tricks

Swap variables

var a = 10 , b = 20 ; 
console.log("a = " + a + " , b = " + b);  // a = 10 , b = 20
b = [a, a = b][0];                        // swap the variables 
console.log("a = " + a + " , b = " + b);  // a = 20 , b = 10

Truncate a value to a Integer in Javascript

Usage Result
~~0.125 0
~~1 1
~~1.6 1
~~"2.59" 2
~~-2.8 -2
~~"Apple" 0
~~[] 0
~~null 0

Note -: It never returns NaN. If it fails, it just returns 0

Check if given input is numeric in Javascript

function isNumeric (arg) {
    return !isNaN(parseFloat(arg)) && isFinite(arg);
}
Usage Result
isNumeric(10) true
isNumeric(10.234) true
isNumeric(0.215) true
isNumeric('10') true
isNumeric('10.234') true
isNumeric('0.215') true
isNumeric('') false
isNumeric('Qwerty') false
isNumeric('43Agd') false