JavaScript - Picking specific data from JSON object

Question

I'm trying to pick specific data from my JSON response which looks like this;

{
   "status": "success",
   "reservations": [
      {
         "id": "26630",
         "subject": "Subject",
         "modifiedDate": "2017-05-16T06:05:12",
         "startDate": "2017-05-16T08:00:00",
         "endDate": "2017-05-16T09:45:00",
         "resources": [
            {
               "id": "2408",
               "type": "student_group",
               "code": "groupCode",
               "name": "groupName"
            },
            {
               "id": "3020",
               "type": "realization",
               "code": "realizationCode",
               "name": "realizationName"
            },
            {
               "id": "48",
               "type": "room",
               "code": "roomCode",
               "parent": {
                  "id": "2",
                  "type": "building",
                  "code": "buildingCode",
                  "name": "buildngName"
               },
               "name": "RoomName (PC)"
            }
         ],
         "description": ""
      },
      {
         "id": "21173",
         "subject": "subjectName",
         "modifiedDate": "2017-05-16T06:05:20",
         "startDate": "2017-05-16T08:00:00",
         "endDate": "2017-05-16T16:00:00",
         "resources": [
            {
               "id": "3115",
               "type": "realization",
               "code": "realizationCode",
               "name": "realizationName"
            },
            {
               "id": "2584",
               "type": "student_group",
               "code": "groupCode",
               "name": "groupName"
            },
            {
               "id": "52",
               "type": "room",
               "code": "roomCode",
               "parent": {
                  "id": "2",
                  "type": "building",
                  "code": "buildingCode",
                  "name": "buildingName"
               },
               "name": "roomName (classroom)"
            }
         ],
         "description": ""
      }
   ]
}

I've already used JSON.parse() to make it into an object and went through it with for-loops;

var json = JSON.parse(data.responseText);

for (var i = 0; i < json.reservations.length; i++) {
    if (json.reservations[i].resources != null) {
        for (var j = 0; j < json.reservations[i].resources.length; j++) {

             var reservations = json.reservations[i];
             var resources = json.reservations[i].resources[j];  

         }                              
     }
}

So I would need to pick out the room names before the "description" key name:

"name": "roomName (PC)"
"name": "roomName (classroom)"

I've kept the JSON response a lot shorter for simplicity's sake but usually there's many more of these room names. The idea is to get all the room names from the JSON response body and push them to an array and just printing them out in order like this;

roomName (PC)
roomName (classroom)

Any quick and effective way to do this?

I think you might want to use lodash.js or underscore.js for this.. It's really helpful.. — JMS786, May 16 '17 at 10:30

score 4 · Answer 1 · edited May 23 '17 at 12:26

4

You can use such way:

const arrays = json.reservations
  .filter(reservation => reservation.resources)
  .map(reservation =>
    reservation.resources.map(resource => resource.name)
  )
;

const names = [].concat.apply([], arrays);

Array flatten taken from this question: Merge/flatten an array of arrays in JavaScript?

edited May 23 '17 at 12:26

Community

1
1

answered May 16 '17 at 10:29

lunochkin

626
3
16

also you can use lodash to flatten arrays – lunochkin May 16 '17 at 10:31
That's true, but I prefer your current answer (some explanation would be nice) as the OP didn't ask for a library, nor was it tagged or used. – evolutionxbox May 16 '17 at 10:35
basically, you are getting array of arrays with names and then flattening result array – lunochkin May 16 '17 at 10:37
If you're answer is taken from http://stackoverflow.com/questions/10865025/merge-flatten-an-array-of-arrays-in-javascript surely then this question is a duplicate? – evolutionxbox May 16 '17 at 10:38
no, there is only this part: `const names = [].concat.apply([], arrays);` – lunochkin May 16 '17 at 10:38

Yosvel Quintero Arguelles · Accepted Answer · 2017-05-16T11:34:20.553

You can first iterate over the json.reservations array with Array.prototype.forEach() and then iterate again over r.resources and make a Array.prototype.push() if the expression: new RegExp(/roomName/, 'i').test(r.name) is satisfied.

Notice that in your json array have lowercase "name": "roomName (classroom)" and uppercase "name": "RoomName (PC)", so the Regular Expression will not check case sensitive with the flag i and finally the RegExp.prototype.test() will check if roomName is in the r.name.

Code:

var json = {"status": "success","reservations": [{"id": "26630","subject": "Subject","modifiedDate": "2017-05-16T06:05:12","startDate": "2017-05-16T08:00:00","endDate": "2017-05-16T09:45:00","resources": [{"id": "2408","type": "student_group","code": "groupCode","name": "groupName"},{"id": "3020","type": "realization","code": "realizationCode","name": "realizationName"},{"id": "48","type": "room","code": "roomCode","parent": {"id": "2","type": "building","code": "buildingCode","name": "buildngName"},"name": "RoomName (PC)"}],"description": ""},{"id": "21173","subject": "subjectName","modifiedDate": "2017-05-16T06:05:20","startDate": "2017-05-16T08:00:00","endDate": "2017-05-16T16:00:00","resources": [{"id": "3115","type": "realization","code": "realizationCode","name": "realizationName"},{"id": "2584","type": "student_group","code": "groupCode","name": "groupName"},{"id": "52","type": "room","code": "roomCode","parent": {"id": "2","type": "building","code": "buildingCode","name": "buildingName"},"name": "roomName (classroom)"}],"description": ""}]},
    result = [],
    regex = new RegExp(/roomName/, 'i');

json.reservations.forEach(function (r) {
  r.resources.forEach(function (r) {
    regex.test(r.name) && result.push({
      name: r.name
    });
  });
})

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

score 1 · Answer 3 · answered May 16 '17 at 10:32

You can simply do this:

var a = {
   "status": "success",
   "reservations": [
      {
         "id": "26630",
         "subject": "Subject",
         "modifiedDate": "2017-05-16T06:05:12",
         "startDate": "2017-05-16T08:00:00",
         "endDate": "2017-05-16T09:45:00",
         "resources": [
            {
               "id": "2408",
               "type": "student_group",
               "code": "groupCode",
               "name": "groupName"
            },
            {
               "id": "3020",
               "type": "realization",
               "code": "realizationCode",
               "name": "realizationName"
            },
            {
               "id": "48",
               "type": "room",
               "code": "roomCode",
               "parent": {
                  "id": "2",
                  "type": "building",
                  "code": "buildingCode",
                  "name": "buildngName"
               },
               "name": "RoomName (PC)"
            }
         ],
         "description": ""
      },
      {
         "id": "21173",
         "subject": "subjectName",
         "modifiedDate": "2017-05-16T06:05:20",
         "startDate": "2017-05-16T08:00:00",
         "endDate": "2017-05-16T16:00:00",
         "resources": [
            {
               "id": "3115",
               "type": "realization",
               "code": "realizationCode",
               "name": "realizationName"
            },
            {
               "id": "2584",
               "type": "student_group",
               "code": "groupCode",
               "name": "groupName"
            },
            {
               "id": "52",
               "type": "room",
               "code": "roomCode",
               "parent": {
                  "id": "2",
                  "type": "building",
                  "code": "buildingCode",
                  "name": "buildingName"
               },
               "name": "roomName (classroom)"
            }
         ],
         "description": ""
      }
   ]
}

var b = [];
a.reservations.forEach(function(item){ 
    item.resources.forEach(function(obj){  
        if(obj.type == "room"){
            b.push(obj.name)
        }  
    })  
});
console.log(b); //outputs desired array

score 0 · Answer 4 · answered May 16 '17 at 11:30

var jsonStr = "{ \"status\": \"success\", \"reservations\": [ { \"id\": \"26630\", \"subject\": \"Subject\", \"modifiedDate\": \"2017-05-16T06:05:12\", \"startDate\": \"2017-05-16T08:00:00\", \"endDate\": \"2017-05-16T09:45:00\", \"resources\": [ { \"id\": \"2408\", \"type\": \"student_group\", \"code\": \"groupCode\", \"name\": \"groupName\" }, { \"id\": \"3020\", \"type\": \"realization\", \"code\": \"realizationCode\", \"name\": \"realizationName\" }, { \"id\": \"48\", \"type\": \"room\", \"code\": \"roomCode\", \"parent\": { \"id\": \"2\", \"type\": \"building\", \"code\": \"buildingCode\", \"name\": \"buildngName\" }, \"name\": \"RoomName (PC)\" } ], \"description\": \"\" }, { \"id\": \"21173\", \"subject\": \"subjectName\", \"modifiedDate\": \"2017-05-16T06:05:20\", \"startDate\": \"2017-05-16T08:00:00\", \"endDate\": \"2017-05-16T16:00:00\", \"resources\": [ { \"id\": \"3115\", \"type\": \"realization\", \"code\": \"realizationCode\", \"name\": \"realizationName\" }, { \"id\": \"2584\", \"type\": \"student_group\", \"code\": \"groupCode\", \"name\": \"groupName\" }, { \"id\": \"52\", \"type\": \"room\", \"code\": \"roomCode\", \"parent\": { \"id\": \"2\", \"type\": \"building\", \"code\": \"buildingCode\", \"name\": \"buildingName\" }, \"name\": \"roomName (classroom)\" } ], \"description\": \"\" } ] }";
var json = JSON.parse(jsonStr);
var array = [];  
for (var i = 0; i < json.reservations.length; i++) {
    if (json.reservations[i].resources != null) {

        for (var j = 0; j < json.reservations[i].resources.length; j++) {
             var resource = json.reservations[i].resources[j];
             if (resource.type === "room") {
                 if (array.indexOf("code")) {
                     array.push(resource.name);
                 }                                     
             }                                                                                         
         }

     }
}
 console.log(array);

output in console. Please check..

(2) ["RoomName (PC)", "roomName (classroom)"]0: "RoomName (PC)"1: "roomName (classroom)"length: 2__proto__: Array(0)

JavaScript - Picking specific data from JSON object

4 Answers4