How to get objects from array nested in another object in array with ES6

Question

I have data with the following structure:

var DATA = {
'device_groups': [{
  'id': '1',
  'name': 'group 1',
  'devices': [{
    'id': 11,
    'name': 'device 11',
    'active': 1
  }, {
    'id': 12,
    'name': 'device 12',
    'active': 0
  }, {
    'id': 13,
    'name': 'device 13',
    'active': 0
  }] 
}, {
  'id': '2',
  'name': 'group 2',
  'devices': [{
    'id': 21,
    'name': 'device 21',
    'active': 1
  }, {
    'id': 22,
    'name': 'device 22',
    'active': 0
  }, {
    'id': 23,
    'name': 'device 23',
    'active': 1
  }]
}, {
  'id': '3',
  'name': 'group 3',
  'devices': [{
    'id': 31,
    'name': 'device 31',
    'active': 1
  }, {
    'id': 32,
    'name': 'device 32',
    'active': 0
  }, {
    'id': 33,
    'name': 'device 33',
    'active': 1
  }]  
}]
};

From all these "device_groups" arrays and inner "devices" arrays I need to get a single array of objects where 'active' is true (1).

How to do it the ES6+ way?

Answer 1

You can use map and filter like this:

 var DATA={'device_groups':[{'id':'1','name':'group 1','devices':[{'id':11,'name':'device 11','active':1},{'id':12,'name':'device 12','active':0},{'id':13,'name':'device 13','active':0}]},{'id':'2','name':'group 2','devices':[{'id':21,'name':'device 21','active':1},{'id':22,'name':'device 22','active':0},{'id':23,'name':'device 23','active':1}]},{'id':'3','name':'group 3','devices':[{'id':31,'name':'device 31','active':1},{'id':32,'name':'device 32','active':0},{'id':33,'name':'device 33','active':1}]}]} const filtered = DATA.device_groups.map(a => a.devices.filter(a => a.active === 1)), output = [].concat(...filtered); console.log(output) 

Or using a simple reduce

 var DATA={'device_groups':[{'id':'1','name':'group 1','devices':[{'id':11,'name':'device 11','active':1},{'id':12,'name':'device 12','active':0},{'id':13,'name':'device 13','active':0}]},{'id':'2','name':'group 2','devices':[{'id':21,'name':'device 21','active':1},{'id':22,'name':'device 22','active':0},{'id':23,'name':'device 23','active':1}]},{'id':'3','name':'group 3','devices':[{'id':31,'name':'device 31','active':1},{'id':32,'name':'device 32','active':0},{'id':33,'name':'device 33','active':1}]}]} const devices = DATA.device_groups .reduce((a,d) => a.concat(d.devices.filter(f => f.active)),[]); console.log(devices) 

Answer 2

You can do it using reduce and filter .

By filter we take out only the elements from devices which are having status active and than we concat them in final output

 var DATA={'device_groups':[{'id':'1','name':'group 1','devices':[{'id':11,'name':'device 11','active':1},{'id':12,'name':'device 12','active':0},{'id':13,'name':'device 13','active':0}]},{'id':'2','name':'group 2','devices':[{'id':21,'name':'device 21','active':1},{'id':22,'name':'device 22','active':0},{'id':23,'name':'device 23','active':1}]},{'id':'3','name':'group 3','devices':[{'id':31,'name':'device 31','active':1},{'id':32,'name':'device 32','active':0},{'id':33,'name':'device 33','active':1}]}]} let output = DATA.device_groups.reduce((op,cur)=>{ let temp = cur.devices.filter(ele=> ele.active) op = op.concat(temp) return op; },[]) console.log(output) 

Answer 3

basically you can use reduce and filter to achieve what you want

 var DATA = { 'device_groups': [{ 'id': '1', 'name': 'group 1', 'devices': [{ 'id': 11, 'name': 'device 11', 'active': 1 }, { 'id': 12, 'name': 'device 12', 'active': 0 }, { 'id': 13, 'name': 'device 13', 'active': 0 }] }, { 'id': '2', 'name': 'group 2', 'devices': [{ 'id': 21, 'name': 'device 21', 'active': 1 }, { 'id': 22, 'name': 'device 22', 'active': 0 }, { 'id': 23, 'name': 'device 23', 'active': 1 }] }, { 'id': '3', 'name': 'group 3', 'devices': [{ 'id': 31, 'name': 'device 31', 'active': 1 }, { 'id': 32, 'name': 'device 32', 'active': 0 }, { 'id': 33, 'name': 'device 33', 'active': 1 }] }] }; const deviceGroups = DATA.device_groups; const solution = deviceGroups.reduce((result, devicegroup) => { const filteredDevices = devicegroup.devices.filter(device => device.active === 1) return [...result, ...filteredDevices] }, []) console.log(solution) 

Answer 4

Using reduce merge the inner array of devices from every device_groups into one array of devices . Then filter the merged array with active === 1 to get one single array of devices which are active.

 var DATA = {"device_groups":[{"id":"1","name":"group 1","devices":[{"id":11,"name":"device 11","active":1},{"id":12,"name":"device 12","active":0},{"id":13,"name":"device 13","active":0}]},{"id":"2","name":"group 2","devices":[{"id":21,"name":"device 21","active":1},{"id":22,"name":"device 22","active":0},{"id":23,"name":"device 23","active":1}]},{"id":"3","name":"group 3","devices":[{"id":31,"name":"device 31","active":1},{"id":32,"name":"device 32","active":0},{"id":33,"name":"device 33","active":1}]}]}; var devices = DATA.device_groups .reduce((acc, ele) => { acc = acc.concat([...ele['devices']]); //merging each device array with the next with the concat(). return acc; },[]) .filter((data) => data['active'] === 1); console.log(devices); 

Answer 5

you can use just forEach and spread ... operator and push filtered results where active property is true, in final array

 var DATA = {'device_groups': [{'id': '1','name': 'group 1','devices': [{'id': 11,'name': 'device 11','active': 1}, {'id': 12,'name': 'device 12','active': 0}, {'id': 13,'name': 'device 13','active': 0}] }, {'id': '2','name': 'group 2','devices': [{'id': 21,'name': 'device 21','active': 1}, {'id': 22,'name': 'device 22','active': 0}, {'id': 23,'name': 'device 23','active': 1 }]}, {'id': '3','name': 'group 3','devices': [{'id': 31,'name': 'device 31','active': 1}, {'id': 32,'name': 'device 32','active': 0}, {'id': 33,'name': 'device 33','active': 1}]}]}; const result =[]; DATA.device_groups.forEach(devGroup => result.push(...devGroup.devices.filter(d => d.active))); console.log(result);