[Javascript] How to check if a string contains only numbers?

The simplest way is by using regex. Check the below example to check if the given string contains only numbers.

let str1 = '12345';
let str2 = 'e45';

let regex = /^\d+$/;
console.log(regex.test(str1)); // outputs true
console.log(regex.test(str2)); // outputs false

Run here https://onecompiler.com/javascript/3xnrm3ped

We try to determine whether the string we are trying to check contains only entirely numeric characters using the regular expression / [0-9] + /. The character "/" serves as the expression's separator at both the beginning and finish, according to an analysis of this expression. It's crucial to be aware that other delimiters, such as (),, [], >, or #, can be used as start and end delimiters. For instance: # [0-9] + # See this link

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