Trouver la clé depuis une position d'index AP (avancé)

{
    "index": 1,
    "rank": 1,
    "key": {
        "property1": "string",
        "property2": "string"
    },
    "resource": {
        "allocations": [
            {
                "amount": 800,
                "charter_code": "8000",
                "charter_id": 180,
                "description": "Fournitures",
                "line_index": 1
            }
        ],
        "amounts": {
            "subtotal": 800,
            "total": 920
        },
        "code": "AP-2026-00087",
        "date": "2026-03-01T00:00:00",
        "description": "Achat fournitures mars",
        "id": 502,
        "invoice_type": {
            "code": "invoice",
            "id": 2,
            "label": "Facture"
        },
        "metadata": {
            "sdk_index_used": 1,
            "sdk_interface": "TransAP",
            "unique_id": 33021,
            "updated_at": "2026-03-05T14:00:00-05:00",
            "updated_by_user_id": 7
        },
        "payable": 0,
        "reference": "INV-88931",
        "status": {
            "is_active": true,
            "is_deleted": false,
            "is_paid_in_full": false
        },
        "supplier": {
            "code": "F-10010",
            "id": 45
        },
        "supplier_paid_to": {
            "code": "F-10010",
            "id": 45
        },
        "terms": {
            "term_due_days": 30,
            "term_number_of_days": 30,
            "term_percent": 0,
            "term_type": 0
        }
    }
}