setwatch doesn't work stable

Hello,

I'm using setwatch to detetch keypress events. I wired up a pin as button. Voltage flows as "5V -> Button -> E2 Pin"
I'm using STMF32F4 Discovery.

Here is my code :

var button1=E2;

pinMode(button1, "input_pulldown");


setWatch(function(e) {
       console.log(e);
        }, button1, { repeat: true, edge: "both",debounce:10});

Some times it prints console while I'm not pressing button. Some times prints 2-3 times on a button press. Some times it doesn't print anything. So, I can't understand which is the real button press event;

Here is the output :

{ "state": true, "lastTime": undefined, "time": 2106.83884495238 } 
{ "state": false, "lastTime": 2106.83884495238, "time": 2107.13843809523 }
{ "state": true, "lastTime": 2107.13843809523, "time": 2102.44481219047 } 
{ "state": false, "lastTime": 2102.44481219047, "time": 2108.03721752380 }
{ "state": false, "lastTime": 2108.03721752380, "time": 2106.63911619047 }
 { "state": true, "lastTime": 2106.63911619047, "time": 2106.43938742857 } 
{ "state": true, "lastTime": 2106.43938742857, "time": 2107.33816685714 } 
{ "state": false, "lastTime": 2107.33816685714, "time": 2107.53789561904 } 
{ "state": true, "lastTime": 2107.53789561904, "time": 2107.13843809523 } 
{ "state": true, "lastTime": 2107.13843809523, "time": 2108.03721752380 } 
{ "state": false, "lastTime": 2108.03721752380, "time": 2107.13843809523 } 
{ "state": false, "lastTime": 2107.13843809523, "time": 2122.91701028571 } 
{ "state": false, "lastTime": 2122.91701028571, "time": 2122.91701028571 } 
{ "state": false, "lastTime": 2122.91701028571, "time": 2126.01280609523 } 
{ "lastTime": 2126.01280609523, "time": 2126.81172114285, "pin": E2, "state": true } 
{ "state": false, "lastTime": 2126.81172114285, "time": 2127.11131428571 } 
{ "state": true, "lastTime":2127.11131428571, "time": 2127.11131428571 } 
{ "state": true, "lastTime": 2127.11131428571, "time": 2125.81307733333 } 
{ "state": false, "lastTime": 2125.81307733333, "time": 2132.90344838095 } 
{ "state": true, "lastTime": 2132.90344838095, "time": 2125.91294171428 } 
{ "state": true, "lastTime": 2125.91294171428, "time": 2133.30290590476 } 
{ "state": false, "lastTime": 2133.30290590476, "time": 2133.50263466666 } 
{ "state": true, "lastTime": 2133.50263466666, "time": 2132.40412647619 } 
{ "state": true, "lastTime": 2132.40412647619, "time": 2131.90480457142 } 
{ "state": false, "lastTime": 2131.90480457142, "time": 2133.60249904761 }