/**
 * Copyright (c) HashiCorp, Inc.
 * SPDX-License-Identifier: MPL-2.0
 */
type Accessor = (d: any) => any;
/**
 * A utility class that contains an accessor function
 * and metadata.
 *
 * Encodings are used by marks to model what properties of
 * a mark can be "encoded" (derivded from a scale and a dataset).
 */
declare class Encoding {
    /** The name of a the field when the Encoding is using a field accessor;
     * `undefined` otherwise. */
    field?: string;
    /** The accessor function that will return the appropriate value from
     * a dataset for the encoding. */
    accessor: Accessor;
    /**
     * Creates an Accessor and captures metadata.
     *
     * ```
     * const fieldAccessor = new Accessor('avg');
     * const customAccessor = new Accessor(d => d.high - d.low);
     * const staticAccessor = new Accessor(12);
     *
     * const datum = {
     *   avg: 100,
     *   high: 112,
     *   low: 78,
     * };
     *
     * console.log(fieldAccessor.accessor(datum)); // 100
     * console.log(customAccessor.accessor(datum)); // 34
     * console.log(staticAccessor.accessor(datum)); // 12
     * ```
     *
     * @param accessor - When the accessor is a `function`, the function is the accessor.
     *                   When the accessor is a `string`, the string is a field accessor.
     *                   When the accessor is a `number`, the accessor always returns that number.
     */
    /**
     * Creates an Accessor and captures metadata.
     *
     * ```
     * const fieldAccessor = new Accessor('avg');
     * const customAccessor = new Accessor(d => d.high - d.low);
     * const staticAccessor = new Accessor(12);
     *
     * const datum = {
     *   avg: 100,
     *   high: 112,
     *   low: 78,
     * };
     *
     * console.log(fieldAccessor.accessor(datum)); // 100
     * console.log(customAccessor.accessor(datum)); // 34
     * console.log(staticAccessor.accessor(datum)); // 12
     * ```
     *
     * @param accessor - When the accessor is a `function`, the function is the accessor.
     *                   When the accessor is a `string`, the string is a field accessor.
     *                   When the accessor is a `number`, the accessor always returns that number.
     */
    constructor(accessor: string | number | Accessor);
}
export { Accessor, Encoding };