ts-data-forge/src/functional/ternary-result/impl/ternary-result-is-warn.mts

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import { WarnTypeTagName } from './tag.mjs';
import { type NarrowToWarn } from './types.mjs';

/**
 * Type guard for the Warn variant.
 *
 * @example
 *
 * ```ts
 * const maybeWarn = TernaryResult.warn('value', 'check logs') as TernaryResult<
 *   string,
 *   string,
 *   string
 * >;
 *
 * if (TernaryResult.isWarn(maybeWarn)) {
 *   assert.strictEqual(maybeWarn.value, 'value');
 *
 *   assert.strictEqual(maybeWarn.warning, 'check logs');
 * }
 * ```
 */
export const isWarn = <R extends UnknownTernaryResult>(
  result: R,
): result is NarrowToWarn<R> => result.$$tag === WarnTypeTagName;