Validation with Joi in NestJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import Joi for validation.

NestJS

import * as [1] from 'joi';

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Aexpress

BJoi

Cnestjs

Dclass-validator

Attempts:

3 left

💡 Hint

Common Mistakes

Importing from 'express' or 'nestjs' instead of 'joi'.

Using 'class-validator' which is a different validation library.

Joi is imported as a namespace to use its validation functions.

2fill in blank

medium

Complete the code to define a Joi schema for a username that is a required string.

NestJS

const schema = Joi.object({ username: Joi.[1]().required() });

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Anumber

Barray

Cboolean

Dstring

Attempts:

3 left

💡 Hint

Common Mistakes

Using number() or boolean() instead of string().

Forgetting to call required() to make the field mandatory.

The username should be a string, so we use Joi.string().

3fill in blank

hard

Fix the error in the validation pipe setup by completing the missing property.

NestJS

app.useGlobalPipes(new ValidationPipe({ whitelist: [1] }));

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Afalse

Bnull

Ctrue

Dundefined

Attempts:

3 left

💡 Hint

Common Mistakes

Setting whitelist to false or null disables property filtering.

Leaving whitelist undefined means no filtering happens.

Setting whitelist: true removes properties not in the DTO.

4fill in blank

hard

Fill both blanks to create a Joi schema for an email that is required and must be valid.

NestJS

const schema = Joi.object({ email: Joi.[1]().[2]() });

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Astring

Bemail

Crequired

Dvalid

Attempts:

3 left

💡 Hint

Common Mistakes

Using email() instead of string() (email is a validator, not a type).

Forgetting to add required().

Email should be a string and required, so use string() and required().

5fill in blank

hard

Fill all three blanks to create a Joi schema for a password that is a required string with minimum length 8.

NestJS

const schema = Joi.object({ password: Joi.[1]().min([2]).[3]() });

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Astring

B8

Crequired

Dnumber

Attempts:

3 left

💡 Hint

Common Mistakes

Using number() instead of string().

Forgetting to call required().

Setting min to a string instead of a number.

Password must be a string, at least 8 characters, and required.