export interface HasCustomFields {
    /**
     * Points at the schema in `erpCustomFieldsSchemas` that should validate `customFields`.
     * Omit (undefined) to avoid unintentionally overwriting existing server-side values.
     */
    customFieldsSchemaRef?: number | null;
    /**
     * Schema-bound custom fields stored on the ERP entity.
     * Omit (undefined) to avoid unintentionally overwriting existing server-side values.
     */
    customFields?: Record<string, unknown> | null;
}
/**
 * Apply `customFields` and `customFieldsSchemaRef` to an outgoing API payload.
 *
 * IMPORTANT: We only set fields when they are not `undefined` (null is allowed) to avoid
 * unintended overwrites when callers don't specify custom fields.
 */
export declare function applyCustomFields<T extends Record<string, unknown>>(obj: T, customFields: Pick<HasCustomFields, "customFieldsSchemaRef" | "customFields">): T;
/**
 * Convenience helper to construct a "full" API payload from a REST-style payload.
 */
export declare function toFullApiObjectFromRest(restObj: Record<string, unknown>, source: HasCustomFields): Record<string, unknown>;
/**
 * Merge non-empty `customFields` into a REST payload. Returns a shallow copy so callers can
 * keep a strict `Record<string, string>` base type before widening with optional `customFields`.
 */
export declare function applyNonEmptyCustomFieldsToRest<T extends Record<string, unknown>>(obj: T, customFields: Record<string, unknown> | null | undefined): T & {
    customFields?: Record<string, unknown>;
};
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