import { LogLevel } from '../log-levels.constant.js';
/**
 * The environment variable that sets the default log levels of `ConsoleLogger`.
 */
export declare const LOG_LEVEL_ENV_VAR = "NEST_LOG_LEVEL";
/**
 * Reads the log levels from the `NEST_LOG_LEVEL` environment variable.
 * Accepts the formats of `filterLogLevels`: a level (`warn`, that level and
 * above), a list (`warn,error`) or a threshold (`>=warn`, `>debug`).
 *
 * @returns `undefined` when the variable is unset or empty, `false` when its
 * value can't be parsed, the log levels otherwise.
 */
export declare function getEnvLogLevels(): LogLevel[] | false | undefined;