How to change first boolean of object in array react native?

Question

I have a JSON from API, the response of API is to declare if the task already done,

example of JSON :

[ { Name: 'Pre Operation', Checked: false },
  { Name: 'Operation', Checked: false },
  { Name: 'Post Operation', Checked: false } ]

How can I update a JSON to be like :

[ { Name: 'Pre Operation', Checked: true},
  { Name: 'Operation', Checked: false },
  { Name: 'Post Operation', Checked: false } ]

I have tried using this code:

var output = jsonResult.map((item)=>{
  if(item.Checked == true){
    item.Checked === false
  }
  return item
})

But the JSON doesnt change, and I'm afraid item.Checked === false will effected all of item.Checked that has true value

and if I have a response from API like this:

[ { Name: 'Pre Operation', Checked: true},
  { Name: 'Operation', Checked: false },
  { Name: 'Post Operation', Checked: false } ]

I need to update a JSON to be like this:

    [ { Name: 'Pre Operation', Checked: true},
  { Name: 'Operation', Checked: true},
  { Name: 'Post Operation', Checked: false } ]

Anyone can help me how to archieve my goal?

Is this array of objects (it's not JSON) part of your `this.state`? — T.J. Crowder, May 30 '18 at 09:09
@T.J.Crowder yep, actually I've `parse` JSON from API, and I got those Array when `console.log` — flix, May 30 '18 at 09:10
Please read [What is the difference between JSON and Object Literal Notation?](https://stackoverflow.com/questions/2904131/what-is-the-difference-between-json-and-object-literal-notation) — str, May 30 '18 at 09:11

Nikhil Aggarwal · Accepted Answer · 2018-05-30T09:13:25.873

Use Array.find

var arr = [ { Name: 'Pre Operation', Checked: false }, { Name: 'Operation', Checked: false }, { Name: 'Post Operation', Checked: false } ];
  
  function updateStatus(){
    var result = arr.find(({Checked}) => !Checked); 
    if(result) result.Checked = true;
  }
  
 updateStatus(); console.log(arr); // first is updated
 updateStatus(); console.log(arr); // second is updated
 updateStatus(); console.log(arr); // third is updated
 updateStatus(); console.log(arr); // no update

score 0 · Answer 2 · answered May 30 '18 at 09:14

Not sure if I'm misunderstanding the question, but surely you can just..

jsonResult[0].Checked = true;

edit.. if you want to be less ruthless..

jsonResult.some((item) => { if (item.Name = 'Pre Operation') { item.Checked = true; return true; })

array.prototype.some is a good way to exist a loop when you've done what you need - once 'true' is returned it will stop looping.

How to change first boolean of object in array react native?

2 Answers2