function mergeItems(iIndex, oldItems, newItems, desc) { const index = indices[iIndex]; const items = [ ...new Set( [ ...newItems.map((item) => ({ ...item, action: index.action, key: index.key, index: iIndex, })), ...oldItems, ].map((i) => JSON.stringify(i)) ), ].map((i) => JSON.parse(i)); items.sort((a, b) => a.blockHeight - b.blockHeight); if (desc) { items.reverse(); } return items; } return { mergeItems };