Answers for "if variable is a number javascript"

40

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!
}
Posted by: Guest on December-12-2020
0

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
Posted by: Guest on May-21-2020
4

javascript check if variable is number

function isNumber(n) {
  return !isNaN(parseFloat(n)) && !isNaN(n - 0);
}
Posted by: Guest on May-22-2020
0

check if a variable is a number in javascript

// as test cases we have two variables of which 1 is a number and the second one is a string
let x = 7;
let y = "hello"
let result1 = !Number.isNaN(x) // true
let result2 = !Number.isNaN(y) // flase
Posted by: Guest on June-01-2021
0

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');
}
Posted by: Guest on December-27-2020

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