Here’s an example of a Yup validation logic where the first input field is optional but, if filled, it must contain only alphabetic characters, and the second input field is required: import * as Yup from “yup”; const validationSchema = Yup.object().shape({ firstField: Yup.string().matches(/^[A-Za-z]*$/, { message: “First field must contain only …

Jest is a JavaScript unit testing framework created by Facebook. I usually use mocha for unit testing Node.js code, but when it comes to testing React, Jest combined with Enzyme is pretty much the best. Enzyme is a JavaScript utility library created by Airbnb. It lets you simulate DOM rendering …