Delete key/value pairs of multiple JSON objects

Question

I have an array with multiple JSON objects. I don't need all key/values in my file so I want to delete e.g. all "Completed" keys and their values across all of those JSON objects. I know I could delete specific key/value pairs with the delete operator though leaving undefined holes in the array. I don't want that because I think it will cause problems later on when I work with the array.

I also tried it with splice:

data.splice(data[i].Completed, data.length);

Did I make a mistake with splice?

Acutally I want to create a new file without certain key/values. In my approaches I just manipulated the existing file without creating a new one … how could I do that?

var data = [
{
    "ID": 1,
    "Titel": "ui sketch",
    "Completed": "yes",
    "Prio": 3,
    "Importance": 2
  },
  {
    "ID": 2,
    "Titel": "coding",
    "Completed": "yes",
    "Prio": 4,
    "Importance": 4
  },
  {
    "ID": 5,
    "Titel": "meeting",
    "Completed": "no",
    "Prio": 3,
    "Importance": 2
  },
]

please add what youi want, the same array with deleted objects, or just a new array without completed items? — Nina Scholz
– Nina Scholz, Commented May 26, 2017 at 8:30
splice would be for removing array data, not key/value in your objects. If you only want to remove the "Completed": "yes" key/value, and not the entire object containing that value, splice wouldn't do the trick. — Randy
– Randy, Commented May 26, 2017 at 8:31
I want the same array with deleted key/value pairs e.g. "Completed":"yes" and "Completed":"no". But I want to also do this with more complex key/value pairs that differ a lot from each other in each object e.g. "latitude":"123.23324.21", "longitutde":"3432.23242.31" — Unknown User
– Unknown User, Commented May 26, 2017 at 8:50
@Randy what would do the trick then? When I try it with map() the browser doesn't load the file ... Could this be due to my 200.000 objects in the array? Is that just to much for map()? — Unknown User
– Unknown User, Commented May 27, 2017 at 14:23

Lazyexpert · Accepted Answer · 2017-05-26 10:05:43Z

2

If you need to remove all objects with key 'Completed' equals 'yes' you do:

const newData = data.filter(el => el.Completed !== 'yes')

If you need to remove all keys Completed in case they are equal to 'yes', you do:

const newData = data.map(el => {
  if (el.Completed === 'yes') delete el.Completed
  return el;
})

In most common case for objects you use delete and for Arrays you use splice.

edited May 26, 2017 at 10:05

answered May 26, 2017 at 8:31

Lazyexpert

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Comments

Gabri T · Accepted Answer · 2017-05-26 08:41:37Z

0

var data = [
{
    "ID": 1,
    "Titel": "ui sketch",
    "Completed": "yes",
    "Prio": 3,
    "Importance": 2
  },
  {
    "ID": 2,
    "Titel": "coding",
    "Completed": "yes",
    "Prio": 4,
    "Importance": 4
  },
  {
    "ID": 5,
    "Titel": "meeting",
    "Completed": "no",
    "Prio": 3,
    "Importance": 2
  },
]

var i =data.length-1;
for(i ; i>= 0;i--){
    if(data[i].Completed == "yes"){
        data.splice( i, 1 );
    }
}
alert(data[0].Titel);

here you have it, search for completed == "yes" , if so , splice it, you end up with an array with 1 element :) hope it helps

answered May 26, 2017 at 8:41

Gabri T

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Comments

Yosvel Quintero · Accepted Answer · 2017-05-26 08:44:56Z

0

What I understood from your question is that you want to delete all Completed properties from the objects in the data array.

In that case, you can use Array.prototype.map() to make a new array with objects that have the properties you want:

var data = [{"ID": 1,"Titel": "ui sketch","Completed": "yes","Prio": 3,"Importance": 2},{"ID": 2,"Titel": "coding","Completed": "yes","Prio": 4,"Importance": 4},{"ID": 5,"Titel": "meeting","Completed": "no","Prio": 3,"Importance": 2}],
    result = data.map(elem => {
      return {
        ID: elem.ID,
        Titel: elem.Titel,
        Prio: elem.Prio,
        Importance: elem.Importance
      };
    });

console.log(result);

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

edited May 26, 2017 at 8:44

answered May 26, 2017 at 8:33

Yosvel Quintero

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1 Comment

Unknown User Over a year ago

Thanks Yosvel. Your solution works on my given example. Unfortunately it doesn't seem to work on very large datasets. +50mb … The browser is unable to load the file …

Rohìt Jíndal · Accepted Answer · 2017-05-29 06:31:14Z

0

Try this :

var data = [
{
    "ID": 1,
    "Titel": "ui sketch",
    "Completed": "yes",
    "Prio": 3,
    "Importance": 2
  },
  {
    "ID": 2,
    "Titel": "coding",
    "Completed": "yes",
    "Prio": 4,
    "Importance": 4
  },
  {
    "ID": 5,
    "Titel": "meeting",
    "Completed": "no",
    "Prio": 3,
    "Importance": 2
  }
];

var data = data.map(item => { 
  return {
    "ID": item.ID,
    "Titel": item.Titel,
    "Prio": item.Prio,
    "Importance": item.Importance
  }
});

console.log(data);

answered May 29, 2017 at 6:31

Rohìt Jíndal

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Comments

Graham · Accepted Answer · 2017-09-23 00:24:33Z

0

You can use Array.prototype.filter() methods: documentation on MDN.

Here what it looks like:

var data = [
{
    "ID": 1,
    "Titel": "ui sketch",
    "Completed": "yes",
    "Prio": 3,
    "Importance": 2
  },
  {
    "ID": 2,
    "Titel": "coding",
    "Completed": "yes",
    "Prio": 4,
    "Importance": 4
  },
  {
    "ID": 5,
    "Titel": "meeting",
    "Completed": "no",
    "Prio": 3,
    "Importance": 2
  },
]

// New array from former one.
var undone = data.filter(obj => obj["Completed"] != "yes");

// Skim data from completed elements
data = data.filter(obj => obj["Completed"] != "yes");

edited Sep 23, 2017 at 0:24

Graham

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answered May 26, 2017 at 8:38

hsolatges

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