Joi validation of array

trying to validate that an array has zero or more strings in one case and that it has zero or more objects in another , struggling with Joi docs :(

validate: {
	    headers: Joi.object({
                'content-type': "application/vnd.api+json",
                accept: "application/vnd.api+json"
        }).options({ allowUnknown: true }),
		payload : Joi.object().keys({
			data : Joi.object().keys({
				type: Joi.any().allow('BY_TEMPLATE').required(),
				attributes: Joi.object({
					to : Joi.string().email().required(),
					templateId : Joi.string().required(),
					categories : Joi.array().items( //trying to validate here that each element is a string),
					variables : Joi.array({
						//also trying to validate here that each element is an Object with one key and value
					})
				})
			}).required()
		})
	}

Joi.array().items() accepts another Joi schema to use against the array elements. So an array of strings is this easy:

Joi.array().items(Joi.string())

Same for an array of objects; just pass an object schema to items():

Joi.array().items(Joi.object({
    // Object schema
}))

If you want to validate an array of strings in Joi:

Joi.array().items(Joi.string().valid("item1", "item2", "item3", "item4"))

you can try this:

function(data) {
 const Schema = {
   categories: Joi.array().items(Joi.string()),
   variables: Joi.array().items(Joi.object().keys().min(1))
 }
 return Joi.validate(data, Schema)
}

for more details checkout this repo: https://github.com/raysk4ever/nodejs_withMongoRefArray

You can also try this way, I have been using it for long time and working fine for me.

If your array is array of objects than use below:

const Joi = require('joi');

let schema = Joi.object().keys({
            items: Joi.array().items(
                Joi.object({
                    item_id: Joi.number().required(),
                    item_qty: Joi.number().required(),
                    item_type_id: Joi.number().required(),
                    item_qty: Joi.number().required(),
                    base_price: Joi.number().required(),
                    actual_price: Joi.number().required(),
                })
            ).required(),
        });

        let errors = Joi.validate(req.body, schema);

if you array is simple array than:

let schema = Joi.object().keys({
                items: Joi.array().items(
                Joi.number().required()
            ).min(10).required(),
            });

Joi.array().items(Joi.string().required(), Joi.number().required()); found it here

Validation when we have an array of objects using Joi:

const schema = Joi.array().items(
Joi.object().keys({
  id: Joi.number().required(),
  name: Joi.string().required(),
}));

We could add validations for objects inside an array itself.

validate: {
	    headers: Joi.object({
                'content-type': "application/vnd.api+json",
                accept: "application/vnd.api+json"
        }).options({ allowUnknown: true }),
		payload : Joi.object().keys({
			data : Joi.object().keys({
				type: Joi.any().allow('BY_TEMPLATE').required(),
				attributes: Joi.object({
					to : Joi.string().email().required(),
					templateId : Joi.string().required(),
					categories : Joi.array().items(Joi.string()),
					variables : Joi.array().items(Joi.object().keys().max(1))
				})
			}).required()
		})
	}