Joi Nested schema

Question

I am trying to create nested schema in joi and it is throwing error

[Error: Object schema cannot be a joi schema]

var nestedSchema = joi.object({
    b: joi.number()
});

var base = joi.object({
    a: joi.string(),
    nestedData:joi.object(nestedSchema)
});

How should i define nested schema in joi?

Answer 1

Although Francesco's answer works, there's no need to use object.keys(). The error the question creator was doing is to pass a schema as a parameter to joi.object().

So, creating nested schemas is as simple as assigning a schema to a key belonging to another schema.

const schemaA = Joi.string()
const schemaB = Joi.object({ keyB1: schemaA, keyB2: Joi.number() })
const schemaC = Joi.object({
  keyC1: Joi.string(),
  keyC2: schemaB  
})

Joi.validate({ keyC1: 'joi', keyC2: { keyB1: 'rocks!', keyB2: 3 } }, schemaC)

Answer 2

You could use object.keys API

var nestedSchema = joi.object().keys({
    b: joi.number()
});

var base = joi.object({
    a: joi.string(),
    nestedData: nestedSchema
});

Answer 3

just a tip based on Francesco's accepted answer:

if you need "nestedData" to be required -> "nestedData: nestedSchema.required()" in "base" will not work, you need to set it directly on "nestedSchema" just like any other parameter

    var nestedSchema = joi.object().keys({
        b: joi.number()
    })
    .required();

    var base = joi.object({
        a: joi.string(),
        nestedData: nestedSchema
    });

Answer 4

With Joi version 17.6.0 you can use the valid function as below

const schema = Joi.object({
   type: Joi.string().valid('android', 'ios').insensitive()
})

This will throw an error if the type property is not android or ios

Answer 5

const base = joi.object({
     a: joi.string(),
     nestedData: joi.object({b: joi.number()})
});