Let’s follow this article to learn how to check if string is a positive integer using JavaScript with the explanation and examples below. Read this article now.
Check If String Is A Positive Integer Using JavaScript
To check if string is a positive integer using JavaScript, you have to convert a string to an integer or a number.
Next, if you convert it to a number, you have to check if it is an integer or not.
Then, you can get the result of the problem by checking if the result of the previous step is greater than or equal to 0 or not.
You can learn more about methods that can help you convert a string to a number or an integer here.
Use the parseInt() method
You can convert the string to an integer by the parseInt() method. So you can get the result by comparing it with 0.
Look at the example below to learn more about this method.
// This is the function that helps you check if String is a Positive Integer.
function isPositiveInteger(str){
// Check if a String can be a Float or not.
if (str.includes('.')) return false
let value = parseInt(str)
if (isNaN(value)) return false
if ( value < 0 ) return false
return true
}
let str1 = '1'
let str2 = 'LearnShareIT'
let str3 = '0.5'
let str4 = '-1'
let str5= '0'
console.log(isPositiveInteger(str1))
console.log(isPositiveInteger(str2))
console.log(isPositiveInteger(str3))
console.log(isPositiveInteger(str4))
console.log(isPositiveInteger(str5))
Output
true
false
false
false
true
Use the Number object
Firstly, you convert the string to a number.
Secondly, check if the number is an integer or not by using the isInteger() method.
Finally, check if an integer is greater than or equal to 0.
You will get the result of the task.
Syntax
Number.isInteger(value)
Parameters
- value: The value you want to check.
Return Value:
True if the value is an integer. Otherwise false.
Look at the example below:
// This is the function that helps you check if String is a Positive Integer.
function isPositiveInteger(str){
let value = Number(str)
if ( isNaN(value) || Number.isInteger(value) == false) return false
if (value < 0 ) return false
return true
}
let str1 = '1'
let str2 = 'LearnShareIT'
let str3 = '0.5'
let str4 = '-1'
let str5= '0'
console.log(isPositiveInteger(str1))
console.log(isPositiveInteger(str2))
console.log(isPositiveInteger(str3))
console.log(isPositiveInteger(str4))
console.log(isPositiveInteger(str5))
Output
true
false
false
false
true
Summary
You can check if string is a positive integer using JavaScript by using the parseInt() method or the Number object. Choose the method that is suitable for you. We hope this guide is helpful to you. Thanks!
Maybe you are interested:
- Check if a Number is NaN in JavaScript
- Check if a Character is a Number using JavaScript
- Convert a Negative Number to Positive in JavaScript
- How To Convert A Positive Number To Negative Using JavaScript?

My name is Thomas Valen. As a software developer, I am well-versed in programming languages. Don’t worry if you’re having trouble with the C, C++, Java, Python, JavaScript, or R programming languages. I’m here to assist you!
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Programming Languages: C, C++, Java, Python, JavaScript, R