Find the first unique value in an array or string

Question

How can I get one unique value in an array or string? Only the first value. Pure JS only.

My example:

function searchValue () {
  let inputText = [1,1,4,2,2,2,3,1];
  let foundedValue;
  for (let i = 0; i < inputText.length; i++) {
    if (i === inputText.indexOf(inputText[i]) && i === inputText.lastIndexOf(inputText[i])) {
      foundedValue = inputText[i];
      break;
    } else {
      foundedValue = "not founded.";
    }
  }
  return foundedValue;
}
console.log("Search value: "+ searchValue())

Answer is 4.

But, I need a short solution. Using the find() and filter() functions.

Answer 1

You can find the first unique item in your array using find() and comparing indexOf() to lastIndexOf() to determine whether or not there is more than one instance of an item in the array. If you need to find unique characters in a string, then you can first split it into an array and then use the same approach.

const arr = [1, 1, 4, 2, 2, 2, 3, 1];
const result = arr.find((x) => arr.indexOf(x) === arr.lastIndexOf(x));
console.log(result);
// 4

const text = 'aadbbbca';
const textarr = text.split('');
const textresult = textarr.find((x) => textarr.indexOf(x) === textarr.lastIndexOf(x));
console.log(textresult);
// d