How to set value to json object from another json object?

Question

I have two json objects: a, b. I need to set seqNo to b json object from a json object based on the id. How would I go about doing this?

var a = [{id: "Make",   seqNo: 4},
            {id: "Model",  seqNo: 1},
            {id: "XModel", seqNo: 2},
            {id: "Rate",   seqNo: 3},
            {id: "Price",  seqNo: 0}];

var b = [
           {id: "Make", field: "make", seqNo: setvalue},
           {id: "Model", field: "model", seqNo: setvalue},
           {id: "XModel", field: "model", seqNo: setvalue},
           {id: "Rate", field: "price", seqNo: setvalue},
           {id: "Price", field: "price", seqNo: setvalue}
        ];

output:-

var c = [
            {headerName: "Make", field: "make", seqNo: 4},
            {headerName: "Model", field: "model", seqNo: 1},
            {headerName: "XModel", field: "model", seqNo: 2},
            {headerName: "Rate", field: "price", seqNo: 3},
            {headerName: "Price", field: "price", seqNo: 0}
        ];

you want manually? check if(a[0].id == "Make"){ b[0].seqNo = a[0]['seqNO']; } — SamiMalik, Feb 25 '16 at 07:04
Same type of discussion found at http://stackoverflow.com/questions/21450060/how-to-join-two-json-object-in-javascript-without-using-jquery — NeoAsh, Feb 25 '16 at 07:20

ChrisY · Answer 1 · 2016-02-25T09:45:33.337

I would try something like this:

var mapped_a = a.reduce(function(result, element) {
    result[element.id] = element.seqNo;
    return result;
}, {});

// mapped_a => {Make: 4, Model: 1,.. }

var mapped_b = b.map(function(element) {
    var newElement = {
        id: element.id,
        field: element.field,
        seqNo: mapped_a[element.id]
    };
    return newElement;
});

In the first step I convert the array to an object map. Then I can access the correct element via the array syntax in the map function.

score 1 · Answer 2 · answered Feb 25 '16 at 07:14

Assuming same order:

var setvalue="";
var a = [{id: "Make",   seqNo: 4},
         {id: "Model",  seqNo: 1},
         {id: "XModel", seqNo: 2},
         {id: "Rate",   seqNo: 3},
         {id: "Price",  seqNo: 0}];

var b = [{id: "Make", field: "make", seqNo: setvalue},
         {id: "Model", field: "model", seqNo: setvalue},
         {id: "XModel", field: "model", seqNo: setvalue},
         {id: "Rate", field: "price", seqNo: setvalue},
         {id: "Price", field: "price", seqNo: setvalue}
        ];

var c=[];
for (var i=0;i<a.length;i++) {
  var aItem = a[i], bItem=b[i];
  c.push({ headerName:aItem.id, field:bItem.field, seqNo: aItem.seqNo });
}
console.log(c);
document.write(JSON.stringify(c, null, 2).replace(/},/g,"},<br/>"));

Alexander Bychkov · Answer 3 · 2016-02-25T08:17:35.630

0

If you're using underscorejs you should use the following code for merge two objects

_.extend({id: "Make", field: "make", seqNo: setvalue}, {id: "Make", seqNo: 4})

If you're using Jquery then this code

$.extend({id: "Make", field: "make", seqNo: setvalue}, {id: "Make", seqNo: 4})

If you need a plain javascript function you can find it at: http://youmightnotneedjquery.com/

So, you have two arrays of objects, so you need use map or another method to go through your array and apply for each element the extending function.

edited Feb 25 '16 at 08:17

answered Feb 25 '16 at 07:09

Alexander Bychkov

78
1
8

How to do in AngularJS? @Sasha Bichkov – Suresh B Feb 25 '16 at 07:13
I think that's what you need: http://stackoverflow.com/questions/28473574/angularjs-merge-two-objects – Alexander Bychkov Feb 25 '16 at 07:16

score 0 · Answer 4 · answered Feb 25 '16 at 07:45

here is the looping solution assuming you have equal number of objects in both array to get the satisfying result

var a = [{id: "Make",   seqNo: 4},
            {id: "Model",  seqNo: 1},
            {id: "XModel", seqNo: 2},
            {id: "Rate",   seqNo: 3},
            {id: "Price",  seqNo: 0}];

var b = [
           {id: "Make", field: "make", seqNo: 'setvalue'},
           {id: "Model", field: "model", seqNo: 'setvalue'},
           {id: "XModel", field: "model", seqNo: 'setvalue'},
           {id: "Rate", field: "price", seqNo: 'setvalue'},
           {id: "Price", field: "price", seqNo: 'setvalue'}
        ];

b = b.map(function (obj) {
    a.forEach(function (aObj,aIndex) {
        if (obj.id == a[aIndex].id) {
            obj["seqNo"] = a[aIndex].seqNo;
        }
    })
    return obj;
})
console.log(b)

// Sample result
[ { id: 'Make', field: 'make', seqNo: 4 },
  { id: 'Model', field: 'model', seqNo: 1 },
  { id: 'XModel', field: 'model', seqNo: 2 },
  { id: 'Rate', field: 'price', seqNo: 3 },
  { id: 'Price', field: 'price', seqNo: 0 } ]

haotang · Answer 5 · 2016-02-26T01:16:01.543

0

Thanks for this challenging question.

This is my solution using lodash:

var c = _.zipWith(b, a, function(obj1, obj2) {
    var object= _.assign({}, obj1, obj2);
    object.headerName = object.id; 
    delete object.id; 
    return object;
});

console.log(c);

edited Feb 26 '16 at 01:16

answered Feb 26 '16 at 00:54

haotang

5,520
35
46

score 0 · Answer 6 · answered Jul 24 '18 at 08:13

Here is Your code :

var a = [{id: "Make",   seqNo: 4},
        {id: "Model",  seqNo: 1},
        {id: "XModel", seqNo: 2},
        {id: "Rate",   seqNo: 3},
        {id: "Price",  seqNo: 0}];

// make it null of seqNo
var b = [
       {id: "Make", field: "make", seqNo: null},
       {id: "Model", field: "model", seqNo: null},
       {id: "XModel", field: "model", seqNo: null},
       {id: "Rate", field: "price", seqNo: null},
       {id: "Price", field: "price", seqNo: null}
    ];

Set Value here

Just Make it :

   if(a.length == b.length){
      for(var i=0; i<a.length;i++){
         b[i].seqNo = a[i].seqNo;
      }
    }
    else{ console.log('Error','length not Match')}

Also Alternate Way :

You can assign directly if you have a two object:

var b = [
       {id: "Make", field: "make", seqNo: a[0].seqNo},
       {id: "Model", field: "model", seqNo: a[1].seqNo},
       {id: "XModel", field: "model", seqNo: a[2].seqNo},
       {id: "Rate", field: "price", seqNo: a[3].seqNo},
       {id: "Price", field: "price", seqNo: a[4].seqNo}
    ];

Hope this help for you...

score -1 · Answer 7 · answered Feb 25 '16 at 07:24

I suggest using for loop in javascript.

var a = [{id: "Make",   seqNo: 4},
        {id: "Model",  seqNo: 1},
        {id: "XModel", seqNo: 2},
        {id: "Rate",   seqNo: 3},
        {id: "Price",  seqNo: 0}];
var b = [
       {id: "Make", field: "make", seqNo: 0},
       {id: "Model", field: "model", seqNo: 0},
       {id: "XModel", field: "model", seqNo: 0},
       {id: "Rate", field: "price", seqNo: 0},
       {id: "Price", field: "price", seqNo: 0 }
    ];
for (var iB in b) {
   for(var iA in a){

   var objB = b[iB];
   var objA = a[iA];
        if(objB.id == objA.id ){
          objB.seqNo = objA.seqNo;
        }
    }
}
console.log(b)

JSfiddle Link

Hope it helps.

Do not use `for in` for arrays. – mplungjan Feb 25 '16 at 07:26 — mplungjan, Feb 25 '16 at 07:26

How to set value to json object from another json object?

7 Answers7