if variable is a number javascript code example
Example 1: javascript check if number
function isNumber(n) { return /^-?[\d.]+(?:e-?\d+)?$/.test(n); }
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isNumber('123');
isNumber('123abc');
isNumber(5);
isNumber('q345');
isNumber(null);
isNumber(undefined);
isNumber(false);
isNumber(' ');
Example 2: javascript check if variable is number
function isNumber(n) {
return !isNaN(parseFloat(n)) && !isNaN(n - 0);
}
Example 3: if parameter is not number in js
let num1 = 'Hello';
if(isNaN(num1)){
console.log(num1 + ' is not a number');
} else{
console.log(num1 + ' is a number');
}