Check if an object is a Promise

isPromise.js

function isPromise(object){
  if(Promise && Promise.resolve){
    return Promise.resolve(object) == object;
  }else{
    throw "Promise not supported in your environment"
  }
}

var i = 1;
var p = new Promise(function(resolve,reject){
  resolve()
});

isPromise(i) // false
isPromise(p) // true