How do I remove a key from a JavaScript object?

Let's say we have an object with this format:

var thisIsObject= {
   'Cow' : 'Moo',
   'Cat' : 'Meow',
   'Dog' : 'Bark'
};

I wanted to do a function that removes by key:

removeFromObjectByKey('Cow');

Answer

The delete operator allows you to remove a property from an object.

The following examples all do the same thing.

// Example 1
var key = "Cow";
delete thisIsObject[key]; 

// Example 2
delete thisIsObject["Cow"];

// Example 3
delete thisIsObject.Cow;

If you're interested, read Understanding Delete for an in-depth explanation.