Three Ways to Find the Longest Word in a String in JavaScript (Recommended)

function findLongestWord(str) {
 return str.length;
}
findLongestWord("The quick brown fox jumped over the lazy dog");

var strSplit = “The quick brown fox jumped over the lazy dog”.split(' ');

var strSplit = ["The", "quick", "brown", "fox", "jumped", "over", "the", "lazy", "dog"];

var strSplit = 
[“T”, “h”, “e”, “ “, “q”, “u”, “i”, “c”, “k”, “ “, “b”, “r”, “o”, “w”, “n”, “ “, “f”, “o”, “x”, “ “, “j”, “u”, “m”, “p”, “e”, “d”, “ “, “o”, “v”, “e”, “r”, “ “, “t”, “h”, “e”, “ “, “l”, “a”, “z”, “y”, “ “, “d”, “o”, “g”];

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. Initiate a variable that will hold the length of the longest word
 var longestWord = 0;

 // Step 3. Create the FOR loop
 for(var i = 0; i < strSplit.length; i++){
 if(strSplit[i].length > longestWord){ // If strSplit[i].length is greater than the word it is compared with...
 longestWord = strSplit[i].length; // ...then longestWord takes this new value
  }
 }
 /* Here strSplit.length = 9
  For each iteration: i = ? i < strSplit.length? i++ if(strSplit[i].length > longestWord)? longestWord = strSplit[i].length
  1st iteration: 0 yes 1 if("The".length > 0)? => if(3 > 0)? longestWord = 3
  2nd iteration: 1 yes 2 if("quick".length > 3)? => if(5 > 3)? longestWord = 5 
  3rd iteration: 2 yes 3 if("brown".length > 5)? => if(5 > 5)? longestWord = 5 
  4th iteration: 3 yes 4 if("fox".length > 5)? => if(3 > 5)? longestWord = 5 
  5th iteration: 4 yes 5 if("jumped".length > 5)? => if(6 > 5)? longestWord = 6 
  6th iteration: 5 yes 6 if("over".length > 6)? => if(4 > 6)? longestWord = 6 
  7th iteration: 6 yes 7 if("the".length > 6)? => if(3 > 6)? longestWord = 6
  8th iteration: 7 yes 8 if("lazy".length > 6)? => if(4 > 6)? longestWord = 6 
  9th iteration: 8 yes 9 if("dog".length > 6)? => if(3 > 6)? longestWord = 6 
  10th iteration: 9 no    
  End of the FOR Loop*/

 //Step 4. Return the longest word
 return longestWord; // 6
}

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

function findLongestWord(str) {
 var strSplit = str.split(' ');
 var longestWord = 0;
 for(var i = 0; i < strSplit.length; i++){
 if (strSplit[i].length > longestWord){
 longestWord = strSplit[i].length;
  }
 }
 return longestWord;
}
findLongestWord("The quick brown fox jumped over the lazy dog");

var sortArray = [“The”, “quick”, “brown”, “fox”, “jumped”, “over”, “the”, “lazy”, “dog”].sort();

var sortArray = ["The", "brown", "dog", "fox", "jumped", "lazy", "over", "quick", "the"];

[].sort(function(firstElement, secondElement) { return secondElement.length — firstElement.length; })

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
 ab 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");

function findLongestWord(str) {
 var longestWord = str.split(' ').sort(function(a, b) { return b.length - a.length; });
 return longestWord[0].length;
}
findLongestWord("The quick brown fox jumped over the lazy dog");

[].reduce(function(previousValue, currentValue) {...}, "");

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. Use the reduce method
 var longestWord = strSplit.reduce(function(longest, currentWord) {
 if (currentWord.length > longest.length)
  return currentWord;
 else
  return longest;
 }, "");
 
 /* Reduce process
 currentWord longest currentWord.length longest.length if(currentWord.length > longest.length)? var longestWord
 "The" "" 3 0 yes "The"
 "quick" "The" 5 3 yes "quick"
 "brown" "quick" 5 5 no "quick"
 "fox" "quick" 3 5 no "quick"
 "jumped" "quick" 6 5 yes "jumped"
 "over" "jumped" 4 6 no "jumped"
 "the" "jumped" 3 6 no "jumped"
 "lazy" "jumped" 4 6 no "jumped"
 "dog" "jumped" 3 6 no "jumped"
 */
 
 // Step 3. Return the length of the longestWord
 return longestWord.length; // var longestWord = "jumped" 
        // longestWord.length => "jumped".length => 6
}

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

function findLongestWord(str) {
 var longestWord = str.split(' ').reduce(function(longest, currentWord) {
 return currentWord.length > longest.length ? currentWord : longest;
 }, "");
 return longestWord.length;
}
findLongestWord("The quick brown fox jumped over the lazy dog");