How to take the third value of an object array

Question

First of all, I’ve already researched about, but I couldn’t, at least not in a simple way and it was supposed to work. Well I have a variable that contains this following array when I give a console

[
 {
  Id: 1,
  User: 'User',
  Password: 'Dn',
  Nome: 'Fhdnd',
  Sobrenome: 'Js'
 } 
]

This is the array of users, but this I want to get only the password? It was not supposed to work with rows[2] ? What I hoped was that you would return:

[
  {
    Password: 'Dn'
  }
]

Error: Undefined

The only way I can achieve this goal is with foreach?

Obs: Rows is the name of the variable that contains this array

My full function where I’m trying to solve the problem

async function verify(req,res,username,password){
 db.serialize(async function (){                               
  const query = 'SELECT * from Users WHERE User = (?) AND Password = (?)'                                                     
 db.all(query,[username, password],async function(err,rows){    
  try{
   if(rows.length == 1){                                          
    console.time("time1")                                         
    await console.log(rows);                                      
    console.log("Correct user");                                                                                                                
    res.render(__dirname + "/View/Home/index.handlebars");
    rows[2]                                          
    console.timeEnd("time1")                                       
     }
    else{
     console.log("Incorrect user!")}}
    catch{
    console.error("\x1b[31m","Problema com a função de autenticação, erro: \n", err);
    }
  })
})}

This is where I want to access the index exactly, I’m calling the function, I just didn’t post everything because this is where the function should show the index I want to access etc ... I’m just not posting the rest because I’m not having a problem with the rest of my code.

It may be that I come from more than one object in the array, ie I will add more users over time.

Answer 1

Buddy, I’ve done three ways here to try to solve your problem. The first is to display in case it is an array with only one object (which was the one initially presented in your question). The other two shapes are distinct ways of doing the same thing when we have a list of objects (an array with multiple objects).

Code in case it is an array with only 1 object:

let usuarios = [{
  Id: 1,
  User: 'User',
  Password: 'Dn',
  Nome: 'Fhdnd',
  Sobrenome: 'Js'
}]

console.log(usuarios[0].Password);

Now two distinct ways of traversing an array of objects (a list of objects), which is what it really seems to be your need.

let usuarios = [{
    Id: 1,
    User: 'User',
    Password: 'Dn',
    Nome: 'Fhdnd',
    Sobrenome: 'Js'
  },
  {
    Id: 2,
    User: 'User2',
    Password: 'Cn',
    Nome: 'Alombra',
    Sobrenome: 'PHP'
  },
  {
    Id: 3,
    User: 'User3',
    Password: 'Fn',
    Nome: 'Dinamic',
    Sobrenome: 'Java'
  }
]

/* 1ª forma */
usuarios.forEach(item => {
  console.log(item.Password);
});

console.log('-----');

/* 2ª forma */
for (key in usuarios) {
  console.log(usuarios[key].Password);
}

I hope I’ve helped.

OBS: Add this part below to give further information on a question that the questioner has shown to have in the comments. Below is an example of an Array and manipulation of it.

Array:

frutas = ["morango", "laranja", "abacaxi", "banana"];

console.log(frutas[3]); //Acessando elemento de um array

• Javascript NAY works with Associative Array, this form below does not work in Javascript (this array statement would work in PHP for example). Behold:

array = ["id" => 1, "nome" => "Bruno", "idade" => 19, "email" => "[email protected]"];
console.log(array["nome"]);

Above, it will give error. To work with associative indexes, in JS, the best way is to work in object form. See the links below for better information:

Arrays

Alternative to work with Associative indexes in JS