Find the longest word using . Sort()

Question

Hello, I would like to be able to do a function to find the longest word among a set of words but only find codes that help to find the longest word within a sentence

Follow the code I made

function findLongestWord(str){
  return str.split(" ").sort(function(a, b){return b.length - a.length})[0];
  
  var words = str.split(" ");
  var longest = "";
  
  for (var word of words) {
    if (word.length > longest.length) longest = word;
  }
  return longest.length
}

console.log(findLongestWord("The", "quick", "brown"));

Answer 1

The way you wrote it, you can use the rest parameter to put all arguments (where args is an array) of function and do the sort the same way you did:

function findLongestWord(...args){
  return 'A maior palavra é: ' + args.sort(function(a, b){return b.length - a.length})[0]; 
}

console.log(findLongestWord("The", "quick", "brown"));
console.log(findLongestWord("Unknow", "quick", "brown"));
console.log(findLongestWord("Unknow", "quick", "brown_for_the_test"));
console.log(findLongestWord("The", "football", "brown"));

Not if your idea was to pass an array as a parameter, but the way you posted in the question, this my solution is possible to meet your requirement.

Answer 2

If you want to pass the words as parameters to the function (as in your example: findLongestWord("The", "quick", "brown")), then one option is to use Rest Parameters:

function findLongestWord(...words) {
    var longest = "";
    for (var word of words) {
        if (word.length > longest.length) longest = word;
    }
    return longest;
}

console.log(findLongestWord("The", "quick", "brown")); // quick

Note the function statement I used ...words to indicate that the number of parameters is variable, and all of them will be placed in words. In the case, words will already be an array, and therefore need not use split or anything like that, just walk through it with for.

And you also don’t need to sort the array: just scroll through it and go checking the size of each string, to find the largest. Sorting has an O(n log n), while traversing the array in a for simple has cost O(n). Sorting the array seems completely unnecessary to me, since you just want to grab the biggest string, and whatever the other (see here a comparison and see how ordering the array makes it slower).

In the end, return the string itself, and not its size (I understood that you want the string, so do not return the length yes to the string itself longest).

Remember that in the case of a tie, the first string found is returned (in the example above, both "Quick" and "Brown" are the largest, and in this case, "Quick" was returned by being in the array at a position prior to "Brown").

---

On older browsers, not ES6 compliant, the Rest Parameters may not be available. In this case, another alternative is to use arguments, which is an object array-like containing all arguments received by the function:

function findLongestWord(){
    var longest = "";
    for (var word of arguments) {
        if (word.length > longest.length) longest = word;
    }
    return longest;
}

console.log(findLongestWord("The", "quick", "brown")); // quick

---

Passing an array

In the comments it was said that you want to pass an array with words to the function. In this case, you would need a small modification:

function findLongestWord(words) { // words agora é um array
    var longest = "";
    for (var word of words) {
        if (word.length > longest.length) longest = word;
    }
    return longest;
}

console.log(findLongestWord([ "The", "quick", "brown" ])); // quick

Now, when calling the function, I passed [ "The", "quick", "brown" ] - note the brackets, they indicate that this is an array (in this case, with 3 elements: the strings "The", "quick" and "brown"). Now the function takes a single parameter, which is the array containing the words.

This is different from findLongestWord("The", "quick", "brown") <- in this case, you are passing 3 parameters to the function (3 separate strings), not an array containing the 3 strings.

It may seem like a silly detail, but it makes a difference if the array is in a variable. See:

function recebeArray(words) {
    var longest = "";
    for (var word of words) {
        if (word.length > longest.length) longest = word;
    }
    return longest;
}

function recebeRestParams(...words) {
    var longest = "";
    for (var word of words) {
        if (word.length > longest.length) longest = word;
    }
    return longest;
}

// array com as palavras
let palavras = [ "The", "quick", "brown" ];

console.log(recebeArray(palavras)); // quick

console.log(recebeRestParams(palavras)); // não funciona
// para funcionar, precisa aplicar o spread operator no array
console.log(recebeRestParams(...palavras)); // quick

To better understand about the Operator spread, read here.