/**
 * To compute the fields in parallel, it is much easier to represent the records as a group of
 * arrays, one array per field.
 *
 * The issue with this transformation is that it is not a bijective function.
 *
 * When we flatten:
 * - { title: 'Foundation', author: { country: null } }
 *
 * After flattening/unflattening, we don't know if the original record was:
 * - { title: 'Foundation', author: { country: null } }
 * - { title: 'Foundation', author: null }
 *
 * This is why we add a special marker to the projection, to keep track of null values.
 */
export declare function withNullMarkers(projection: string[]): string[];
export declare function unflatten(flatList: unknown[][], projection: string[]): unknown[];
export declare function flatten(records: unknown[], paths: string[]): unknown[][];
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