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

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))

Answer 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));