import type { ImmutableDictionary } from "./dictionary.js";
import type { AnyCaller } from "./function.js";
/** Log an error to the console. */
export declare function logError(reason: unknown): void;
/** Is an unknown value an `Error` instance? */
export declare function isError(v: unknown): v is Error & {
    readonly code?: string | undefined;
};
/** Things that can be a message. */
export type PossibleMessage = {
    message: string;
} | string;
/** Return the string message from an unknown value, or return `undefined` if it could not be found. */
export declare function getMessage(input: unknown): string | undefined;
/** Require a message from an unknown value, or throw `RequiredError` if it could not be found. */
export declare function requireMessage(input: PossibleMessage, caller?: AnyCaller): string;
/**
 * Split a string message into lines, look for prefixes like `name:`, and return a dictionary of those named messages.
 * - Full messages strings can have multiple lines separated by `\n` newline.
 * - Named messages are extracted into their own entries in the dictionary.
 * - Unnamed messages are combined into a single entry with the key `""` (empty string).
 */
export declare function splitMessage(input: PossibleMessage): ImmutableDictionary<string>;
/**
 * Join a dictionary of named messages back into a single string.
 * - The `""` (empty string) key is emitted as unnamed lines.
 * - Named messages are emitted as `name: message`, one line per message line.
 * - Empty lines are skipped and each emitted line is trimmed to match `splitMessage()` semantics.
 */
export declare function joinMessage(input: ImmutableDictionary<string>): string;
/**
 * Name a message by applying a `name: ` prefix to it.
 * - Assumes each line in the message is a separate error, so each line has the same prefix applied.
 */
export declare function getNamedMessage(name: string | number, message: string): string;