If Then Else

In This Topic

Draft 04	Draft 06	Draft 07	Draft 2019-09	Draft 2020-12

The 3 properties If, Then, Else make it possible to specify conditional validation rules for a schema. Each of them contains a JSON Schema.

The schema described within the If clause is evaluated against the value in the JSON Instance Document.

If the JSON Instance value passes the validation rules in the If, then the value MUST validate against rules described in the Then property
If the JSON Instance value fails to validate using the rules in the If, then the value MUST validate against rules described in the Else property

If a schema contains a Then or Else with no If, then the Then or Else will be ignored.

Example JSON Schema	Copy Code
"Value": { "type": [ "integer", "string" ], "if": { "type": "integer" }, "then": { "type": "integer", "maximum": 9999, "minimum": 0 }, "else": { "type": "string", "maxLength": 4, "minLength": 1, "pattern": "\\d+" } },

Example JSON Schema

Copy Code

"Value": {
    "type": [
        "integer",
        "string"
    ],
    "if": {
        "type": "integer"
    },
    "then": {
        "type": "integer",
        "maximum": 9999,
        "minimum": 0
    },
    "else": {
        "type": "string",
        "maxLength": 4,
        "minLength": 1,
        "pattern": "\\d+"
    }
},

The schema describes a property called "Value" which can contain a string or a Number.

If the value in the instance document is an integer, then the rules in the Then are applied meaning it must be in the range 0-9999.

If the value is not an integer then it must be a string 1-4 chars long matching the regex pattern "\d+".

Example Valid JSON Instance Document Fragments	Copy Code
"Value" : "1234" "Value" : 1234 "Value" : "0"

Example Invalid JSON Instance Document Fragments	Copy Code
"Value" : "" "Value" : 100000 "Value" : "FRED"