Delete Items From JSON or Remove Variables in JavaScript


In PHP, you can directly remove an item from an array using unset function. But there is no unset function in JavaScript. But there is another function that will remove a variable. It’s called delete. Removing variables isn’t the only thing it does. It can also remove items from a JSON array in JavaScript.

It’s usage is simple. Just pass the array variable with the name of the key. Like this :

delete arr[keyname];

Examples

This is the array we’ll use for examples :

var arr = {
 "Gohan" : "Yipee",
 "Vegeta" : "Goku"
}

We first delete the key “Gohan” :

delete arr["Gohan"];

Now, when you output the array arr, you will not see the key “Gohan” with the value “Yipee”. Here’s how the array will become after the above code is executed :

{
 "Vegeta" : "Goku"
}

Easy as that. You can also use delete for removing variables and functions. But you can’t remove the variable “window”. Example :

var uid = "abc";
delete uid;

Now when you access the variable “uid”, you will get the “undefined” error :

console.log(uid);
// ReferenceError: uid is not defined

delete returns “true” when the deleting was successful and “false” when not successful. You will get “false” when you try to delete variables like window.