check if variable is not 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: check if a variable is a number in javascript
let x = 7;
let y = "hello"
let result1 = !Number.isNaN(x)
let result2 = !Number.isNaN(y)