you may want to do this on the server side:
const aggregation = [
{
$addFields: { value: { $toString: "$_id" }, text: "$name" }
},
{
$project: { _id:0, value:1, text:1 }
}
];
db.yourcollection.aggregate(aggregation);
this one is in javascript/mongo shell format. edit/change it as required to PHP 