Joi-fk-extension

This is an extension for the Joi validation library that allows validation of foreign key style references to other objects.

Joi offers a built in ref validation, but it cannot traverse arrays to look up references.

Usage

const VanillaJoi = require('joi');
const joiFkExtension = require('joi-fk-extension');

const Joi = VanillaJoi.extend(joiFkExtension.fkString);
// number foreign keys are also supported with joiFkExtension.fkNumber

const schema = Joi.array().items(
  Joi.object({
    // require that packageId must equal the packageId field 
    // of one of the items in the 'packages' array of the reference data
    packageId: Joi.string().fk('packages.[].packageId'),
  }),
);

const referenceData = {
  packages: [
    { packageId: 'joi' },
    { packageId: 'hapi' },
  ],
};

const pass = Joi.validate([{ packageId: 'hapi' }], schema, { context: {data: referenceData } );

console.log(pass.error); // null - no error

const fail = Joi.validate([{ packageId: 'commander' }], schema, { context: { data: referenceData } });

console.log(fail.error); //"packageId" "commander" could not be found as a reference to "packages.[].packageId"

API

fk(fkPath)

Requires that the field must refer to a foreign key field referenced by fkPath.

Reference data to search for the reference in must be supplied to Joi in options.context.data (e.g. in a call to Joi.validate(data, schema, options))

• fkPath - The format of fkPath has dot seperated object fields, with search across an array indicated by a pair of square brackets ([])

e.g.:

const referenceData = {
  species: [
    { speciesId: 'tiger' },
  ],
};

const zooSchema = Joi.object({
  animals: Joi.array().items(Joi.object({
    name: Joi.string(),
    speciesId: Joi.string().fk('species.[].speciesId'),
  })),
});

fkPath may be an array of possible foreign key paths instead of a string.

e.g.:

const referenceData = {
  species: [
    { speciesId: 'tiger', alternateId: 'panthera tigris' },
  ],
};

const zooSchema = Joi.object({
  animals: Joi.array().items(Joi.object({
    name: Joi.string(),
    speciesId: Joi.string().fk([
      'species.[].speciesId',
      'species.[].alternateId',
    ]),
  })),
});

options

options.context.data

This extension requires that you pass the data that contains foreign keys in the options.context.data parameter to the validate method. Note that the context object should not be re-used between calls to validate as it is used to cache foreign key lookups for performance reasons.