Finding key value on button click

Below is my code…
I have two buttons name “edit” and “del”.
I want to find the key value on button click event .
How can i do that .
Thanks.

var $1 = go.GraphObject.make; // for conciseness in defining templates

myDiagram = $1(go.Diagram, "myDiagramDiv", // create a Diagram for the DIV HTML element
    {
        initialContentAlignment: go.Spot.Center, // center the content
        "undoManager.isEnabled": true, // enable undo & redo
        hoverDelay: 100, // controls how long to wait motionless (msec) before showing Adornment
        allowDragOut: false
    });


myDiagram.nodeTemplate =
$1(go.Node, "Auto",
  { locationSpot: go.Spot.Center },
  $1(go.Shape, "RoundedRectangle",
    { fill: "orange" }),
  $1(go.Panel, "Horizontal",
    { margin: 3 },
    $1("Button",
      { margin: 2,
        click: edit },
      $1(go.TextBlock, {
                text: '\uf044',
                stroke: '#000',
                margin: 2,
                font: '10px FontAwesome',
                editable: false,
                isMultiline: false
            })),
    $1("Button",
      { margin: 2,
        click: del },
      $1(go.TextBlock, {
                text: '\uf1f8',
                stroke: '#000',
                margin: 2,
                font: '10px FontAwesome',
                editable: false,
                isMultiline: false
            })),
    $1(go.TextBlock,
      new go.Binding("text", "key"))
  )
);

function edit(e,obj) {
    alert(e.key.value);
}
function del(e, obj){
    alert("delete");
}
function showMessage(s) {
document.getElementById("changeMethodsMsg").textContent = s;

}

http://gojs.net/latest/intro/events.html#ClickingAndSelecting

It worked Thanks :)