I have a MongoDB query via mongoose and the result is:
[
{
"tablename": "name1"
},
{
"tablename": "name2"
}
]
but I need it as JSONArray :
{
"tablename": [
"name1",
"name2"
]
}
Is there an easy way to convert?
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3 Answers
The aggregation framework can create the desired result for you. Consider the $group and the $push accumulator operators as follows:
db.collection.aggregate([
{
"$group": {
"_id": null,
"tablename": {
"$push": "$tablename"
}
}
},
{
"$project": {
"_id": 0, "tablename": 1
}
}
])
Sample Output:
/* 0 */
{
"result" : [
{
"tablename" : [
"name1",
"name2"
]
}
],
"ok" : 1
}
You can implement this in mongoose using the aggregate() method, for example:
var pipeline = [
{
"$group": {
"_id": null,
"tablename": {
"$push": "$tablename"
}
}
},
{
"$project": {
"_id": 0, "tablename": 1
}
}
]
Model.aggregate(pipeline).exec(function (err, res){
console.log(res);
})
UPDATE
Change this query to use the aggregation framework:
app.post('/getkost', function(request, response){
var kost = new RegExp(request.body.kost,'i');
Move.find(
{ tablename: { $regex: kost } },
{ tablename: 1, _id: 0 },
function(err, doc) {
response.json(doc);
});
});
to this:
app.post('/getkost', function(request, response){
var kost = new RegExp(request.body.kost, 'i');
var pipeline = [
{
"$match": {
"tablename": { "$regex": kost }
}
},
{
"$group": {
"_id": null,
"tablename": {
"$push": "$tablename"
}
}
},
{
"$project": {
"_id": 0, "tablename": 1
}
}
]
Move.aggregate(pipeline, function(err, res) {
response.json(res);
});
});
9 Comments
Piet
its working for a find query too? I dont want to change any data
chridam
Can you show the
find() query? You can substitute that query with the $match pipeline operator.Piet
app.post('/getkost', function(request,response){ var kost = new RegExp(request.body.kost,'i'); Move.find({tablename: {$regex:kost}},{tablename: 1, _id: 0}, function(err, doc) { response.json(doc); }); });
chridam
@Piet Check out my update, this should give you the desired result using the aggregation framework.
Piet
"$match" : { SyntaxError: Unexpected token : |
try...
var inputArr = [
{
"tablename": "name1"
},
{
"tablename": "name2"
}
];
var jsonArr = {"tablename": []};
for (var i = 0; i < inputArr.length; i++) {
jsonArr.tablename.push(inputArr[i].tablename);
}
Comments
This should work for you:
var json = [{
"tablename": "name1"
}, {
"tablename": "name2"
}]
var arr = {};
json.forEach(function(value, key) {
var tableName = Object.keys(json[key]);
arr[tableName] = arr[tableName] || [];
arr[tableName].push(value[tableName]);
});
console.log(arr);
Keep in mind that Object.keys() will actually return an array - if your array contains more than one key (e.g. {"tablename": "name1", "othertablename": "name2"})
Comments
