JavaScript If Else conditional

Question

I have a JS if/else question. Can I know why, if I enter the correct username and password, the else statement is also executed?

By right, if the username and password is correct, then only the if statement will be executed. How come both are executed? Code as below:

var database = [
  {
    username: "john83reuben",
    password: "12345"
  },
  {
    username: "jdominic",
    password: "12345"
  },
  {
    username: "johnreuban",
    password: "12345"
  }
];

newsfeed =[
  { username: "john83reuben", timeline: "Psalm 118:19. I will extol the Lord at all times; His praise will always be on my lips"},
  { username: "jdominic", timeline: "Psalm 34:1-3. I thank you, Lord, with all my heart; I sing praise to you before the gods."},
  { username: "johnreuban", timeline: "Psalm 138: 1-2. I will give thanks to the Lord because of his righteousness;"}
];

function signIn(user,pass){

  for(let i=0; i < database.length ; i++){
    if(database[i].username === user && database[i].password === pass ){
        console.log(newsfeed);

    }else{
      console.log("Error");
    } 

  }
}

var usernamePrompt = prompt("What is your username?");
var passwordPrompt = prompt("What is your password?");

signIn(usernamePrompt,passwordPrompt);

Because you run your if-statement for every object in your array, so when one of the objects don't match your if your else block will trigger — Nick Parsons
– Nick Parsons, Commented Sep 9, 2020 at 15:11

Antony Acosta · Accepted Answer · 2020-09-09 15:12:47Z

1

You are checking against the whole list of the database var, it will execute the else case when it matches against an item that does not have the right credentials, to avoid that just break out of the loop when you find the correct one

answered Sep 9, 2020 at 15:12

Antony Acosta

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1 Comment

Nick Parsons Over a year ago

Using break will still log "error" for all objects before a correct one is found.

Charlie · Accepted Answer · 2020-09-09 15:17:15Z

1

Use Array.prototype.some method to find out if your user/pass at least matches once.

var result = database.some(item => {
   
    return item.userName === user && item.password === pass

})

console.log(result)

answered Sep 9, 2020 at 15:17

Charlie

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