freeCodeCamp Challenge Guide: Check For The Presence of an Element With indexOf()

Guide
1

Check For The Presence of an Element With indexOf()

Solutions

Solution 1 (Click to Show/Hide) 
function quickCheck(arr, elem) {
  if (arr.indexOf(elem) >= 0) {
    return true;
  }
  return false;
}
console.log(quickCheck(["squash", "onions", "shallots"], "mushrooms"));

Code Explanation

  • A simple if-statement can be used to check whether or not the value returned by the indexOf() function is less than 0.
  • Once the value is discovered then you can return either true or false.
  • demonstrates how a simple if-statement can return the correct result.
Solution 2 (Click to Show/Hide) 
function quickCheck(arr, elem) {
  return arr.indexOf(elem) >= 0 ? true : false;
}
console.log(quickCheck(["squash", "onions", "shallots"], "mushrooms"));

Code Explanation

  • demonstrates how the problem can be solved using the ? : (conditional) operator.
Solution 3 (Click to Show/Hide) 
function quickCheck(arr, elem) {
  return arr.indexOf(elem) != -1;
}
console.log(quickCheck(["squash", "onions", "shallots"], "mushrooms"));

Code Explanation

  • demonstrates how the problem can be solved by directly returning result of the comparison.
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