so i have a login form , and i want to check whether the entered name and password already exists in the JSON object , it will prompt a different message for both cases but thr problem is it's not doing it right , here's the code for more clarity :
function registerInfo(){
var name = document.forms[0].username.value;
var pw = document.forms[0].pw.value
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
var response = JSON.parse(xhttp.responseText);
console.log(response);
if (name === "" || pw === "") {
alert ('please complete all the forms')
}
for (var i = 0; i < response.loginfo.length; i++){
if ( name === response.loginfo[i].username && pw ===
response.loginfo[i].password) {
alert('Welcome back ' + name);
break;
} // if statement curly braces
} // loop curcly braces
for (var i = 0; i < response.loginfo.length; i++){
if ( name != response.loginfo[i].username && pw != response.loginfo[i].pw){
alert('Welcome here new ');
break;
} // if statement curcly braces
} // for
} // ready state if statement curly braces
} // function curly braces
xhttp.open("GET", "login.json", true);
xhttp.send();
return false;
}
and here's the JSON Object for a quick test
{
"loginfo" : [
{
"username" : "moh",
"password" : "lol"
},
{
"username" : "zaki",
"password" : "123"
}
]
}
the problem is when the user enters the username and the password which exists in the JSON object id does alert "Welcome back!" , but also the "welcome here new" , which i don't want to , since the latest alert is for new user which their credentials doesn't exist in the JSON object.
Simplest fix would be not allows second for-loop to be executed, if a match is found, so
Either set a flag if match is found and don't execute second for-loop if that flag is set.
Return
instead of break from first for-loop.
But, you can make your code less verbose by using Array.prototype.some
to check if any value matches
var hasMatch = response.loginfo.some( s => s.username === name && s.password === pw );
hasMatch
returns true
if the match is found
alert( "Welcome " + (hasMatch ? "back" + name : "here new" ) );
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