 # How To Check If String Is A Positive Integer Using JavaScript ## 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.

### 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.

// 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!

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