Checking Whether a Javascript String is a Whole Number | Task

Ole Ersoy
Jun - 09  -  1 min

Scenario

We have a string 2010 and we want to check if it's a year.

Approach

Use isPositiveWholeNumber(value):

function isPositiveWholeNumber(value) {
  return /^\d+$/.test(value);
}

function isWholeNumber(value) {
  return /^-?\d+$/.test(value);
}

console.log(isPositiveWholeNumber(undefined)); // false
console.log(isPositiveWholeNumber(null)); // false
console.log(isPositiveWholeNumber('a')); // false
console.log(isPositiveWholeNumber('1a')); // false
console.log(isPositiveWholeNumber('1')); // true
console.log(isPositiveWholeNumber('1234')); // true
console.log(isPositiveWholeNumber('-23')); // false
console.log(isPositiveWholeNumber(123)); // true
console.log(isPositiveWholeNumber(123n)); // true
console.log(isPositiveWholeNumber('1.2')); // false
console.log(isPositiveWholeNumber('')); // false

Demo