Delete Items From JSON or Remove Variables in JavaScript


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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.