need to find if a specific number is existing or not in a JavaScript array

Question

I am new in javascript and maybe the below code has some return error. what I trying to do is find a specific number in a JavaScript array.

const numberList = [1, 2, 3, 4];

function includes(arrays, searchElement) {
  for (let elements of arrays) {
    if (elements === searchElement) {
      return true;
    } else {
      return false;
    }
  }
}
console.log(includes(numberList, 3))

JavaScript array [already has an includes](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes) — Liam, Dec 09 '19 at 12:07
Also, you get `false` because `return` immediately ends the function. Thus you only get the *first* result of the loop. — VLAZ, Dec 09 '19 at 12:08
you can use `indexOf` to check whether value exist in the array or not — Narendra Chouhan, Dec 09 '19 at 12:12

Mamun · Accepted Answer · 2019-12-10T01:31:33.320

1

You should not return when if the condition is false. Instead you can return false from outside of the loop:

const numberList = [1, 2, 3, 4];

function includes(arrays, searchElement) {
  for (let elements of arrays) {
    if (elements === searchElement) {
      return true;
    }
  }
  return false;
}
console.log(includes(numberList, 3))

Though you can use the built-in includes() to achieve the same:

const numberList = [1, 2, 3, 4];
const IsExist = (numberList, search) => numberList.includes(search)? true : false;
console.log(IsExist(numberList, 3));

edited Dec 10 '19 at 01:31

answered Dec 09 '19 at 12:09

Mamun

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You should still return `false` to be consistent with the boolean results. But that has to happen *after* the loop. – VLAZ Dec 09 '19 at 12:10

need to find if a specific number is existing or not in a JavaScript array

1 Answers1