SOURCE

var data = {
    "tel":"18612341234",
    "timestamp":"1514736000",
    "channel":"SZQF",
     "signmsg":"XXX",
}

var arr = []

for(var key in data){
    arr.push(key)
}
var newArr = arr.sort(function(a,b){return a.localeCompare(b)})
var str = ""
for(var key of newArr){

    str +=  key + "=" +data[key] + "&"
   
}
console.log(str.substr(0, str.length-1))