class Buildermethod

refine()

Adds a refinement check; shorthand for check followed by error.

refine(
  fn: (value: T) => boolean,
  messageOrOptions?:
    | StringConvertible
    | {
        message?: StringConvertible;
      },
): this;

Parameters

• fn — Validation function returning boolean.
• messageOrOptions — Error message or options object with message property.

Return value

This builder, for chaining.

Examples

f.string().refine(s => s.length > 0, "Cannot be empty");
f.number().refine(n => n % 2 === 0, { message: "Must be even" });

Related

• class Builder static
  A class that represents a validation builder for an input value.