When(name, field)

creates a constraint for related field validation, for a specific rule that related to other fields status.

Arguments :

  1. name (string | array): The name of related field started by # as string, or multiple names started by # in a array.
  2. field (Field) : Field validation chain to be checked.

Return :

  • when (When): New When instance that has (or, end) methods with the same Arguments signature and Return of When.

Example

import { Schema, Field, When } from "v4f";

const mySchema = Schema({
    a: Field()
        .string()
        .not.required(),
    b: Field()
        .string()
        .not.required(),
    c: Field()
        .string()
        .not.required({
            // Field c is optional when field a or b is present if not field c will be required.
            constaint: When(
                "#a",
                Field()
                    .any()
                    .not.none()
            ).or(
                "#b",
                Field()
                    .any()
                    .not.none()
            )
        })
});

mySchmea.validate({ a: "value", b: "value" }); // true
mySchmea.validate({ a: "value" }); // true
mySchmea.validate({ b: "value" }); // true
mySchmea.validate({ c: "value" }); // true
mySchmea.validate({}); // false
← SchemaGeneric →