OOP guys Beware!! A function in Javascript is not what you think

When the below snippet was run, I was shocked and I realized that I should be very careful with JavaScript.

function test(){
console.log(“Hello”)
}

var t = test;
t.id=”1";
t();
console.log(t.id);
console.log(typeof(t))

Output:
Hello
1
function

Then i did the research and understood what I have missed while learning JavaScript.

Every function in JavaScript is a Function object.

A function without a return statement will return a default value.
In the case of a constructor called with the new keyword, the default value is the value of its this parameter. For all other functions, the default return value is undefined.