how to remove key value pairs in the js code example

Example 1: javascript remove object key

var obj = {a: 5, b: 3};
delete obj["a"];
console.log(obj); // {b: 3}

Example 2: js remove key from object

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

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

// Example 3
delete thisIsObject.Cow;