Get data from complex Json structure using NodeJs - arrays

Question

json Structure:
{
"id" : "1",
"Data" : [
{
"name" : "abc",
},
{
"name" : "option1",
"position" : [
{
"name" : "option1",
"status" : [
{
"code" : "0",
"value" : "OFF"
},
{
"code" : "1",
"value" : "ON"
}
]
}]
} ]
}
Here,I want to get the data from above complex Json structure.How to do that,
Have tried below code but giving error like;
error: uncaughtException: Cannot read property 'status' of undefined
function myfunc(req,res){
var collectionname = db.collection("col1");
collectionname.find({}).each(function(err, doc) {
if(doc != null)
{
var fdata = [];
for(var i =0;i<doc.Data.length;i++){
fdata.push(doc.Data[i].position.status);
}
console.log("fdata............",fdata);
}
});
}
Please help with the same.

Answer 1

You can use foreach for prevent length undefined.
function myfunc(req,res)
{
let collectionname = db.collection("col1");
collectionname.find({}).each(function(err, doc)
{
if(doc != null)
{
let fdata = [];
for(let i in doc.Data)
{
for(let j in doc.Data[i].position)
{
fdata.push(doc.Data[i].position[j].status);
}
}
console.log("fdata............", fdata);
}
});
}
#MikaelLennholm have right, for(let i in doc.Data) works but not recommanded, be careful not to use it in prototyped or object-built arrays.
EDIT:
function myfunc(req,res)
{
db.collection('col1').find({}).each(function(err, doc)
{
if(err)
{
console.log('[INFOS] Request fail, more details:\n', err);
}
else if(doc)
{
let fdata = [];
if(doc.Data && doc.Data.length)
{
for(let i = doc.Data.length-1; i >= 0; i--)
{
if(doc.Data[i].position && doc.Data[i].position.length)
{
for(let j = doc.Data[i].position.length-1; j >= 0; j--)
{
if(doc.Data[i].position[j].status)
{
fdata = fdata.concat(doc.Data[i].position[j].status);
}
}
}
}
}
console.log("[INFOS] Datas:\n", fdata);
}
});
}

Answer 2

im a newbie at nodejs, hope this's correctly
//I assume this is a object or you can convert from string to object
var data = {
"id": "1",
"Data": [
{
"name": "option1",
"position": [
{
"name": "option1",
"status": [
{
"code": "0",
"value": "OFF"
},
{
"code": "1",
"value": "ON"
}
]
}]
}]
}
var statusArr = data.Data[0].position[0].status;
console.log(...statusArr);
Result: { code: '0', value: 'OFF' } { code: '1', value: 'ON' }

Answer 3

Parse through position array as well
function myfunc(req,res){
var collectionname = db.collection("col1");
collectionname.find({}).each(function(err, doc) {
if(doc != null)
{
var fdata = [];
for(var i =0;i<doc.Data.length;i++){
for(var j =0;j<doc.Data[i].position.length;j++){
fdata.push(doc.Data[i].position[j].status);
}
}
console.log("fdata............",fdata);
}
});
}