Remove JSON element

Question

var json = { ... };
var key = "foo";
delete json[key]; // Removes json.foo from the dictionary.

You can use splice to remove elements from an array.

Do NOT have trailing commas in your OBJECT (JSON is a string notation)

UPDATE: you need to use array.splice and not delete if you want to remove items from the array in the object. Alternatively filter the array for undefined after removing

var data = {
  "result": [{
    "FirstName": "Test1",
    "LastName": "User"
  }, {
    "FirstName": "user",
    "LastName": "user"
  }]
}
console.log(data.result);
console.log("------------ deleting -------------");
delete data.result[1];
console.log(data.result); // note the "undefined" in the array.


data = {
  "result": [{
    "FirstName": "Test1",
    "LastName": "User"
  }, {
    "FirstName": "user",
    "LastName": "user"
  }]
}

console.log(data.result);
console.log("------------ slicing -------------");
var deletedItem = data.result.splice(1,1);
console.log(data.result); // here no problem with undefined.

You can try to delete the JSON as follows:

var bleh = {first: '1', second: '2', third:'3'}

alert(bleh.first);

delete bleh.first;

alert(bleh.first);

Alternatively, you can also pass in the index to delete an attribute:

delete bleh[1];

However, to understand some of the repercussions of using deletes, have a look here

I recommend splice method to remove an object from JSON objects array.

jQuery(json).each(function (index){
        if(json[index].FirstName == "Test1"){
            json.splice(index,1); // This will remove the object that first name equals to Test1
            return false; // This will stop the execution of jQuery each loop.
        }
});

I use this because when I use delete method, I get null object after I do JSON.stringify(json)

For those of you who came here looking for how to remove an object from a JSON array based on object value:

let users = [{"name": "Ben"},{"name": "Tim"},{"name": "Harry"}];

 for (let [i, user] of users.entries()) {
    if (user.name == "Tim") {
        users.splice(i, 1);
    }
 }

User Tim is now removed from JSON array users.

All the answers are great, and it will do what you ask it too, but I believe the best way to delete this, and the best way for the garbage collector (if you are running node.js) is like this:

var json = { <your_imported_json_here> };
var key = "somekey";
json[key] = null;
delete json[key];

This way the garbage collector for node.js will know that json['somekey'] is no longer required, and will delete it.

1. Fix the errors in the JSON: http://jsonlint.com/
2. Parse the JSON (since you have tagged the question with JavaScript, use json2.js)
3. Delete the property from the object you created
4. Stringify the object back to JSON.