import * as postcss from 'postcss';
import { Node } from './node';
/**
 * A type that matches any constructor for {@link T}. From
 * https://www.typescriptlang.org/docs/handbook/mixins.html.
 */
export type Constructor<T> = new (...args: any[]) => T;
/**
 * An explicit field description passed to `cloneNode` that describes in detail
 * how to clone it.
 */
interface ExplicitClonableField<Name extends string> {
    /** The field's name. */
    name: Name;
    /**
     * Whether the field can be set to an explicit undefined value which means
     * something different than an absent field.
     */
    explicitUndefined?: boolean;
}
/** The type of field names that can be passed into `cloneNode`. */
type ClonableField<Name extends string> = Name | ExplicitClonableField<Name>;
/**
 * Creates a copy of {@link node} by passing all the properties in {@link
 * constructorFields} as an object to its constructor.
 *
 * If {@link overrides} is passed, it overrides any existing constructor field
 * values. It's also used to assign {@link assignedFields} after the cloned
 * object has been constructed.
 */
export declare function cloneNode<T extends Pick<postcss.Node, 'source'>>(node: T, overrides: Record<string, unknown> | undefined, constructorFields: ClonableField<keyof T & string>[], assignedFields?: ClonableField<keyof T & string>[]): T;
/**
 * Converts {@link node} into a JSON-safe object, with the given {@link fields}
 * included.
 *
 * This always includes the `type`, `sassType`, `raws`, and `source` fields if
 * set. It converts multiple references to the same source input object into
 * indexes into a top-level list.
 */
export declare function toJSON<T extends Node>(node: T, fields: (keyof T & string)[], inputs?: Map<postcss.Input, number>): object;
/**
 * Returns the longest string (of code units) that's an initial substring of
 * every string in
 * {@link strings}.
 */
export declare function longestCommonInitialSubstring(strings: string[]): string;
/**
 * Returns whether {@link set1} and {@link set2} contain the same elements,
 * regardless of order.
 */
export declare function setsEqual<T>(set1: Set<T>, set2: Set<T>): boolean;
export {};