templateLiteral - API reference

API reference › @evolu/common › Type › templateLiteral

function templateLiteral<Parts>(
  ...parts: {
    readonly [Index in string | number | symbol]: ValidateTemplateLiteralPart<
      Parts[Index]
    >;
  } & TemplateLiteralValidation<Parts>
): TemplateLiteralType<Parts>;

Defined in: packages/common/src/Type.ts:4442

Template literal Type for validation.

Creates a canonical string Type from fixed strings and string-encoded Types.

Use this factory when Output should remain a string. Switch to templateLiteralParser when the individual Type parts should be decoded into a Tuple.

Example

import {
  assertFalse,
  assertOk,
  assertType,
  templateLiteral,
  union,
} from "@evolu/common";

const Language = union("en", "cs");
const Region = union("US", "CZ");
const Locale = templateLiteral(Language, "-", Region);

assertType<"en-US" | "en-CZ" | "cs-US" | "cs-CZ", typeof Locale.Output>();
assertOk(Locale.fromUnknown("cs-CZ"), "cs-CZ");
assertFalse(Locale.is("fr-CZ"));