find longest substring js code example

Example 1: js find longest word in string function

function findLongestWordLength(str) {
  return Math.max(...str.split(' ').map(word => word.length));
}

Example 2: js find longest vword

function findLongestWord(str) {
  // Step 1. Split the string into an array of strings
  var strSplit = str.split(' ');
  // var strSplit = "The quick brown fox jumped over the lazy dog".split(' ');
  // var strSplit = ["The", "quick", "brown", "fox", "jumped", "over", "the", "lazy", "dog"];
  
  // Step 2. Sort the elements in the array
  var longestWord = strSplit.sort(function(a, b) { 
    return b.length - a.length;
  });
  /* Sorting process
    a           b            b.length     a.length     var longestWord
  "The"      "quick"            5            3         ["quick", "The"]
  "quick"    "brown"            5            5         ["quick", "brown", "The"]  
  "brown"    "fox"              3            5         ["quick", "brown", "The", "fox"]
  "fox"      "jumped"           6            3         ["jumped", quick", "brown", "The", "fox"]
  "jumped"   "over"             4            6         ["jumped", quick", "brown", "over", "The", "fox"]
  "over"     "the"              3            4         ["jumped", quick", "brown", "over", "The", "fox", "the"]
  "the"      "lazy"             4            3         ["jumped", quick", "brown", "over", "lazy", "The", "fox", "the"]
  "lazy"     "dog"              3            4         ["jumped", quick", "brown", "over", "lazy", "The", "fox", "the", "dog"]
  */
  
  // Step 3. Return the length of the first element of the array
  return longestWord[0].length; // var longestWord = ["jumped", "quick", "brown", "over", "lazy", "The", "fox", "the", "dog"];
                                // longestWord[0]="jumped" => jumped".length => 6
}

findLongestWord("The quick brown fox jumped over the lazy dog");

Example 3: javascript find the longest string in array

Math.max(...(x.map(el => el.length)));