yup - How to validate that only numbers are in a string?

Validating numbers is common in frontend apps, however, most validating packages do not come with built-in methods to validate numbers in string. When using yup, there are not built-in methods for this, even though the problem is so common as mentioned in Issue #927. Luckily, we have yup-numeric.

Usage

Install yup-numeric along with it’s peer dependencies.

npm install yup-numeric yup bignumber.js

Create your schema and start validating!

import { numeric } from 'yup-numeric';

const schema = numeric().max('2.0').required('This is required');
const value = '1.0000000000000000000000000000000000001';

const result = await schema.validate(value);

Why not use regex?

The problem with using regex is it is difficult to validate whether if a float is valid in string. On top of that, what if you want a min/max restriction? Unless you want to validate an integer and do not need to validate the value against upper/lower bound.