Loop through many arrays in javascript

Question

I'm trying to make a search through three different arrays of strings in Javascript, looking for a name (submitted by user), and if this name is found, I have to return in which array it is located.

Something like that: HTML

let users = ['mario', 'gianni', 'pinotto'];
let admins = ['moana', 'cicciolina', 'selen'];
let mods = ['frodo', 'sam', 'bilbo'];

const form = document.querySelector('form');
const btnNome = document.querySelector('#nome');
let risp = document.querySelector('#risposta');

function search() {

  risp.innerText = '';
  let nome = btnNome.value.trim();

  for (i = 0; i < mods.length; i++) {
    if (nome == mods[i]) {
      risposta.innerText += `${nome} is a moderator`;
      break;
    } else if (i == users.length - 1) {
      for (i = 0; i < admins.length; i++) {
        if (nome == admins[i]) {
          risposta.innerText += `${nome} is an admin`;
          break;
        } else if (i == users.length - 1) {
          for (i = 0; i < users.length; i++) {
            if (nome == users[i]) {
              risposta.innerText += `${nome} is a registered user`;
              break;
            } else if (i == users.length - 1) {
              risposta.innerText += `${nome} NON è registrato`;
              break;
            }
          }
        }
      }
    }
  }
  form.reset();
};

<form>
  <label for="text">Insert name</label>
  <input id="name" type="text" name="text" required/>
  <input type="button" onClick="search()" value="search">
</form>

BUT it doesn't work, and freezes the browser. I think I have mistaken something creating a infinite loop... any ideas? thanks

THANK you everyone for your answers, which were all very useful.

Can you please fix the indentation. That's absolutely terrible to read and understand... — Andreas, Mar 18 '20 at 11:35
There is no element with id `risposta`. Also the variable is `risp` not `risposta` — adiga, Mar 18 '20 at 11:37
You have to define a variable in JavaScript with `var`, `let` or `const` otherwise they are global. You should go with `let` in this case to get a writable variable with block scope. — Andreas, Mar 18 '20 at 11:39
Does this answer your question? [Check if string inside an array javascript](https://stackoverflow.com/questions/14461450/check-if-string-inside-an-array-javascript) — A. Meshu, Mar 18 '20 at 11:45

score 0 · Answer 1 · answered Mar 18 '20 at 11:44

Try this

let users = ['mario', 'gianni', 'pinotto'];
let admins = ['moana', 'cicciolina', 'selen'];
let mods = ['frodo', 'sam', 'bilbo'];

const form = document.querySelector('form');
const btnNome = document.querySelector('#nome');
let risp = document.querySelector('#risposta');

function search() {

  let searchName = btnNome.value;
  risp.innerHTML = 
    checkWithArray(searchName, 'user', users) +
    checkWithArray(searchName, 'admin', admins) +
    checkWithArray(searchName, 'mod', mods);
  console.log(searchName);

  form.reset();
};

function checkWithArray(searchName, title, arr) {
  if (arr.indexOf(searchName) > -1) {
    return `${searchName} is ${title}. `;
  }
  return '';
}

<form>
  <label for="text">Insert name</label>
  <input id="nome" type="text" name="text" required/>
  <input type="button" onClick="search()" value="search">
  <label id="risposta"></label>
</form>

Why should OP do this? What did you change? – Andreas Mar 18 '20 at 11:46 — Andreas, Mar 18 '20 at 11:46
I just refactor the code to be shorter. Hence less bug. – Alex - Tin Le Mar 18 '20 at 12:10 — Alex - Tin Le, Mar 18 '20 at 12:10

Sushmit Sagar · Answer 2 · 2020-03-19T08:23:54.917

You can use Array's includes method to find if element exist in an array:

let users = ["mario", "gianni", "pinotto"];
let admins = ["moana", "cicciolina", "selen"];
let mods = ["frodo", "sam", "bilbo"];

const form = document.querySelector("form");
const btnNome = document.querySelector("#nome");
let risp = document.querySelector("#risposta");

function search() {
  risp.innerText = "";
  let nome = btnNome.value.trim();

  checkWithArray(nome, "user", users);
  checkWithArray(nome, "admin", admins);
  checkWithArray(nome, "moderator", mods);

  form.reset();
}

function checkWithArray(searchName, title, arr) {
  const isFound = arr.includes(searchName);

  if (isFound) {
    let text;

    switch (title) {
      case "user":
        text = `${searchName} is a registered user`;
        break;
      case "admin":
        text = `${searchName} is an admin`;
        break;
      case "moderator":
        text = `${searchName} is a moderator`;
        break;
    }

    risp.innerText += text;
  } else {
    risp.innerText += `${searchName} NON è registrato`;
  }
}

score 0 · Answer 3 · answered Mar 18 '20 at 13:13

User Object.entries, find and includes methods

let users = ["mario", "gianni", "pinotto"];
let admins = ["moana", "cicciolina", "selen"];
let mods = ["frodo", "sam", "bilbo"];

const data = { users, admins, mods };

const search = str => {
  const found = Object.entries(data).find(([key, arr]) => arr.includes(str));
  return found ? found[0] : "";
};

const key = search("sam");
const row = data[key];

console.log(`sam found in ${key} and array is ${row}`);

Loop through many arrays in javascript

3 Answers3