javascript check if number
//Updated dec 2020
// The first 2 Variations return a Boolean
// They just work the opposite way around
// IsInteger
if (Number.isInteger(val)) {
// It is indeed a number
}
// isNaN (is not a number)
if (isNaN(val)) {
// It is not a number
}
// Another option is typeof which return a string
if (typeof(val) === 'number') {
// Guess what, it's a bloody number!
}javascript check if string is number
// native returns true if the variable does NOT contain a valid number
isNaN(num)
// can be wrapped for making simple and readable
function isNumeric(num){
return !isNaN(num)
}
isNumeric(123) // true
isNumeric('123') // true
isNumeric('1e10000') // true (This translates to Infinity, which is a number)
isNumeric('foo') // false
isNumeric('10px') // falsejavascript check if number
// The first 2 Variations return a Boolean
// They just work the opposite way around
// IsInteger
if (Number.isInteger(val)) {
// It is indeed a number
}
// isNaN (is not a number)
if (isNaN(val)) {
// It is not a number
}
// Another option is typeof which return a string
if (typeof(val) === 'number') {
// Guess what, it's a bloody number!
}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(' '); // falsejavascript check if variable is number
function isNumber(n) {
return !isNaN(parseFloat(n)) && !isNaN(n - 0);
}To check if a value is a number in JavaScript
const value = 2
isNaN(value) //false
isNaN('test') //true
isNaN({}) //true
isNaN(1.2) //falseCopyright © 2021 Codeinu
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