从对象列表更新基于另一个列表下划线的属性

Question

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.

Answer 1

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> 

Answer 2

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); 

Answer 3

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); 

Answer 4

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); 

Answer 5

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);