How to use the optional function from joi

joi.optional is a method in the Joi library that allows a schema to optionally accept a value or be undefined.

How does joi.optional work?

Sure! joi.optional is a method in the Joi library that allows a schema to optionally accept a value or be undefined. The joi.optional method takes a single argument, which is the schema to be made optional. It returns a new schema that accepts either the original schema or undefined. Here's an example of how to use joi.optional to make a schema optional: javascript Copy code {{{{{{{ const schema = Joi.object({ name: Joi.string(), age: Joi.optional(Joi.number()), }); const { error, value } = schema.validate({ name: 'John' }); console.log(value); // { name: 'John' } In this example, we create a new Joi.object schema with two properties: name and age. The name property is defined as a Joi.string schema, which means it must be a string. The age property is defined as an optional Joi.number schema, which means it can be either a number or undefined. We then validate an object with only the name property. Since the age property is optional, it does not need to be present in the object. The validate method of the schema is called with the object to validate. The error variable will be undefined if the object is valid, and the value variable will contain the validated object. In this case, the value variable will contain only the name property, since the age property was not provided in the input object. This code demonstrates how to use joi.optional to make a schema optional in the Joi library.

Ai Example

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const Joi = require("joi");

const schema = Joi.object({
  name: Joi.string(),
  age: Joi.optional(Joi.number()),
});

const { error, value } = schema.validate({ name: "John" });

console.log(value); // { name: 'John' }

In this example, we create a new Joi.object schema with two properties: name and age. The name property is defined as a Joi.string schema, which means it must be a string. The age property is defined as an optional Joi.number schema, which means it can be either a number or undefined. We then validate an object with only the name property. Since the age property is optional, it does not need to be present in the object. The validate method of the schema is called with the object to validate. The error variable will be undefined if the object is valid, and the value variable will contain the validated object. In this case, the value variable will contain only the name property, since the age property was not provided in the input object. This code demonstrates how to use joi.optional to make a schema optional in the Joi library.