Question 54634 in Javascript Question posted in
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Find any match in an array of objects – Javascript

I have an array of objects in Javascript, I need to check that the value is in that object to return the id.
I am using the some() function but it only works if it matches the first object

This is the array:

const testObj = [
  {id: 1, nombre: "Juan"},
  {id: 2, nombre: "María"},
  {id: 3, nombre: "Pedro"}
];

This is what I do:

let test = 'María'

let priority;

testObj.some(item => item.nombre === test ? priority = item.id : priority = 7)

This is what it returns:

console.log(priority) // 7

Why doesn’t it return the correct id if the value is found in an object?

Tags:

2

Answers


  1. 0

    The Array.some() method ends as soon as the callback function returns true. Since assigning a truthy value (like 7) is equivalent to true, the some ends when priortiy is 7. Array.some() is used to find if it at least one item matches the criteria, and it’s result is a Boolean (true if at least one matches, false if none). Don’t use it as a simple loop, or to find a specific item.

    Use Array.find() instead. If the item is found, destructure it’s id and assign to priority. Array.find() returns null if it can’t find an item. We can use Nullish coalescing operator (??) to supply a fallback object with the default value of 7.

    const testObj = [
  {id: 1, nombre: "Juan"},
  {id: 2, nombre: "María"},
  {id: 3, nombre: "Pedro"}
];

const test = 'María'

// using destructuring
const { id: priority } = testObj.find(o => o.nombre === test) ?? { id: 7 }
console.log(priority)

// using a ternary
const item = testObj.find(o => o.nombre === test)
const priority2 = item ? item.id : 7
console.log(priority2)

// using optional chaining
const priority3 = testObj.find(o => o.nombre === test)?.id ?? 7;
console.log(priority3)
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  2. 0

    The issue

    You’re setting the value of priority to 7 in the else condition of the ternary operator, which will always execute regardless of whether the value is found or not.

    The solution:

    You can modify your code to set the value of priority only when the value is found in the array.

    let test = 'María';
let priority = null;
const testObj = [ {id: 1, nombre: "Juan"}, {id: 2, nombre: "María"}, {id: 3, nombre: "Pedro"} ];

testObj.some(item => {
  if (item.nombre === test) {
    priority = item.id;
    return true;
  }
});

console.log(priority); // 2

    Using for..of loop:

    let test = 'María';
let priority = 7;

for (const item of testObj) {
  if (item.nombre === test) {
    priority = item.id;
    break;
  }
}

console.log(priority); // 2

    Using find() method:

    let test = 'María';
let priority = testObj.find(item => item.nombre === test)?.id || 7;

console.log(priority); // 2

    Note : using find() or a simple for..of loop with an early break statement can be a better than using some.

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