how to popup menu from mouse event to dom body?

Question

I don't have lot of experience with web .. and i need to do something on web client.

I have some code that someone wrote in reactjs - and i want to popup menu when the user click on right click.

I wrote function that call on the right click event ( stop on this event on the right click ) and on this function i create (dynamicly) the menu.

Now i try to add this menu to the dom-> body and i don't know how to do it.
I also don't know how to add the position of the menu.

The code:

// the func event that call on right click
popupMenuOnRightClick(position){

// create the manu 
var menu = [
    {
        name: 'item1'
        title: 'itemTitle1',
        func: function()
        {
            alert('I am itemTitle1')
        }
    },

    {
        name: 'item2'
        title: 'itemTitle2',
        func: function()
        {
            alert('I am itemTitle2')
        }
    }       
];

document.body.appendChild(menu);


}

My code is nead to be popup from the react code file ( jsx file ).