CODEWITHSUNDEEP
javascriptunderscore.js
Albus Dumbledore
Albus Dumbledore

Reputation: 3

From a list of objects update a property based on another list underscorejs

I have a list of objects 'objlist' and a list of ids 'idlist'.

var objlist = [{id:1, visible:true},{id:2, visible:false},{id:3, visible:false}];
var idlist = [1, 3];

I want the objects in the first list to have value of 'visible' as 'true' for every ids in second list, and the remaining to have value 'false'.

When I try with loop within a loop, I get incorrect result. How to get the proper list.

My attempt:

var objlist = [{id:1, visible:true},{id:2, visible:false},{id:3, visible:false}];
var idlist = [1, 3];
_.each(idlist, function(p) {
  _.each(objlist, function(obj) {
    if (obj.id == p) {

      obj.visible = true;

    } else {
      obj.visible = false;
    }
  });
});

console.log(objlist)
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>

What happens is when the condition breaks in subsequent loops, the values get changed.

Upvotes: 0

Views: 108

Answers (5)

Rajesh
Rajesh

Reputation: 24945

To start with, why you code does not work:

You are looping on idList first and then looping on objlist. So the issue here is, on every iteration, only 1 object can have true for condition. Hence the last one is true.

Following is a sample using underscore:

Note: Other answers have already shown approaches using vanilla JS, but since you already are using underscore, you can check this approach

var objlist = [{id:1, visible:true},{id:2, visible:false},{id:3, visible:false}];
var idlist = [1, 3];
_.each(objlist, function(p) {
  p.visible = _.contains(idlist, p.id)
});

console.log(objlist)
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>

Upvotes: 1

Nikhil Aggarwal
Nikhil Aggarwal

Reputation: 28475

Try following

var objlist = [{id:1, visible:true},{id:2, visible:false},{id:3, visible:false}];
var idlist = [1, 3];

objlist = objlist.map(function(item){
    item.visible = idlist.indexOf(item.id) !== -1;
    return item;
});

console.log(objlist);

Upvotes: 0

Vignesh Raja
Vignesh Raja

Reputation: 8761

This works.

var objlist = [{id:1, visible:true},{id:2, visible:false},{id:3, visible:false}];
var idlist = [1, 3];

for(var index in objlist)
{
    var obj = objlist[index];
    obj.visible = idlist.includes(obj.id);
}

console.log(objlist);

Upvotes: 0

Faly
Faly

Reputation: 13356

You can use array.prototype.map and array.prototype.includes:

var objlist = [{id:1, visible:true},{id:2, visible:false},{id:3, visible:false}];
var idlist = [1, 3];

var result = objlist.map(e => (e.visible = idlist.includes(e.id), e));

console.log(result);

Upvotes: 0

gurvinder372
gurvinder372

Reputation: 68413

Use forEach and includes

objlist.forEach( s => (s.visible = idlist.includes( s.id ) ) );

Demo

var objlist = [{id:1, visible:true},{id:2, visible:false},{id:3, visible:false}];
var idlist = [1, 3];

objlist.forEach( s => (s.visible = idlist.includes( s.id ) ) );

console.log(objlist);

Upvotes: 0

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