How to define a JSON schema that requires at least one of many properties

Question

I would like to know if I can define a JSON schema (draft 4) that requires at least one of many properties possible for an object. I already know of allOf, anyOf and oneOf but just can't figure out how to use them in the way I want.

Here are some example JSON to illustrate :

// Test Data 1 - Should pass {      "email": "[email protected]",     "name": "John Doe" } // Test Data 2 - Should pass {     "id": 1,     "name": "Jane Doe" } // Test Data 3 - Should pass {     "id": 1,     "email": "[email protected]",     "name": "John Smith" } // Test Data 4 - Should fail, invalid email {     "id": 1,     "email": "thisIsNotAnEmail",     "name": "John Smith" }  // Test Data 5 - Should fail, missing one of required properties {     "name": "John Doe" } 

I would like to require at least id or email (also accepting both of them) and still pass validation according to format. Using oneOf fails validation if I provide both (test 3), anyOf passes validation even if one of them is not valid (test 4)

Here is my schema :

{     "$schema": "http://json-schema.org/draft-04/schema#",     "id": "https://example.com",     "properties": {         "name": {             "type": "string"         }     },     "anyOf": [         {             "properties": {                 "email": {                     "type": "string",                     "format": "email"                 }             }         },         {             "properties": {                 "id": {                     "type": "integer"                 }             }         }     ] } 

Can you help me how to achieve correct validation for my use case ?

Answer 1

To require at least one of a set of properties, use required inside a series of anyOf options:

{     "type": "object",     "anyOf": [         {"required": ["id"]},         {"required": ["email"]}         // any other properties, in a similar way     ],     "properties": {         // Your actual property definitions here     } { 

If any of the properties you want is present ("id", "email"), then it will pass the corresponding option in allOf.

Answer 2

You may use minProperties: number (and maxProperties: number if needed). That would shorten the schema definition:

{      type: "object",      minProperties: 1,      properties: [/* your actual properties definitions */],      additionalProperties: false } 

Link to documentation: https://json-schema.org/understanding-json-schema/reference/object.html#size