/**
 * Assigns unique values an index number in the order they are encountered.
 *
 * Used to keep categorical GPU encodings stable: once a value gets an index,
 * it must never change for the lifetime of the owning scale.
 *
 * TODO: What about undefined?
 *
 * @template T
 */
export default function createIndexer<T>(): {
    (value: T): number;
    addAll(iterable: Iterable<T>): void;
    invert(value: number): T;
    domain(): T[];
};
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