Literal

Use ft.Literal to validate an unknown value is exactly equal to a specific value. This is most useful in unions.

Union of literals

import * as ft from "funtypes";

export const ObjectKindSchema = ft.Union(
  ft.Literal("USER"),
  ft.Literal("POST"),
);
// => ft.Codec<"USER" | "POST">

export type ObjectKind = ft.Static<typeof ObjectKindSchema>;
// => "USER" | "POST"


// ✅ Valid value
assert.deepEqual(ObjectKindSchema.parse("USER"), "USER");
assert.deepEqual(ObjectKindSchema.parse("POST"), "POST");

// 🚨 Invalid value
assert.throws(() => ObjectKindSchema.parse(42));

// 🚨 Invalid value
assert.throws(() => ObjectKindSchema.parse("SOME_OTHER_STRING"));å