import { type MaybeMap } from '../value/maybe.type';
import { type ObjectFieldEqualityChecker } from './object.equal';
import { type EmptyArray } from '../array/array';
/**
 * A partial "delta" of the given entry. It only contains values that changed from the last entry.
 *
 * - Undefined field values mean the entry should inherit the previous entry's values.
 * - Null field values in a field mean the value has been cleared and should be excluded from future entries.
 */
export type CompressedObjectDeltaArrayDeltaEntry<T extends object> = MaybeMap<T>;
/**
 * A compressed object array.
 *
 * The first object is always fully expanded. Objects are in order of the delta changes.
 */
export type CompressedObjectDeltaArray<T extends object> = [T, ...CompressedObjectDeltaArrayDeltaEntry<T>[]];
/**
 * Compresses the input objects array to a CompressedObjectDeltaArray.
 */
export type ObjectDeltaArrayCompressorCompressFunction<T extends object> = ((uncompressed: T[]) => CompressedObjectDeltaArray<T>) & ((uncompressed: EmptyArray) => EmptyArray);
/**
 * Expands a CompressedObjectDeltaArray to an array of objects.
 */
export type ObjectDeltaArrayCompressorExpandFunction<T extends object> = ((compressed: CompressedObjectDeltaArray<T>) => T[]) & ((compressed: EmptyArray) => EmptyArray);
/**
 * Configuration for an object delta array compressor.
 */
export interface ObjectDeltaArrayCompressorConfig<T extends object> {
    /**
     * Fields to capture as part of the compressor.
     */
    readonly equalityChecker: ObjectFieldEqualityChecker<T>;
}
/**
 * An object delta array compressor.
 */
export interface ObjectDeltaArrayCompressor<T extends object> {
    readonly _equalityChecker: ObjectFieldEqualityChecker<T>;
    readonly compress: ObjectDeltaArrayCompressorCompressFunction<T>;
    readonly expand: ObjectDeltaArrayCompressorExpandFunction<T>;
}
/**
 * Creates an {@link ObjectDeltaArrayCompressor} that can compress and expand arrays of objects using delta encoding.
 *
 * The first object is stored fully. Subsequent objects store only fields that changed from the previous entry.
 * Null in a delta entry means the field was cleared. Undefined (missing key) means no change.
 *
 * @param config - Configuration with the equality checker that defines which fields to track
 * @returns A compressor with `compress` and `expand` methods
 */
export declare function objectDeltaArrayCompressor<T extends object>(config: ObjectDeltaArrayCompressorConfig<T>): ObjectDeltaArrayCompressor<T>;