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This blog post is part of a series. You must finish part-1, part-2, part-3, part-4, part-5, part-6, part-7, part-8, part-9, part-10 & part-11 before continuing here.
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Displaying login error messages

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If you try to log in using the wrong email address or password or both, you would see an error message as shown below.

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Displaying registration error messages

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If you try to register for the second time using the same email address that you used to register the first time, you will receive an error message as shown below.

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In addition to client-side validation, we are also doing server-side validation. In order to make sure that server-side validation is working as expected, we will temporarily comment out the highlighted code line as shown below in the RegisterForm.js file.

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This means that we will not get any validation error messages even if we try to register using an invalid email address. However, we are checking for the validity of the email address server-side in the validate.js file. So, if I register using an invalid email address (hemanta@com for example) registrationValidation(req.body) will produce an error and the error message should be displayed on top of the form.

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If you check the userRoutes.js file, you will see a highlighted line of code as shown below.

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Go to part-13

\n","frontmatter":{"title":"Implement JWT Based User Authentication in a MERN Stack App - Part 12","date":"2021-05-24"}}},"pageContext":{"slug":"/implement-jwt-based-user-authentication-in-a-mern-stack-app-part-12/","prev":{"fields":{"slug":"/implement-jwt-based-user-authentication-in-a-mern-stack-app-part-13/"},"frontmatter":{"modules":null}},"next":{"fields":{"slug":"/implement-jwt-based-user-authentication-in-a-mern-stack-app-part-10/"},"frontmatter":{"modules":null}}}}, "staticQueryHashes": ["3159585216"]}