Easy peasy reverse words

#todayilearned #javascript #beginners

Return string with n or more lettered words reversed, given that string consists of letters and spaces only. (i.e. n is the word length)

A single line clever solution would be by using regex.
If n is predetermined, like n = 5,

const revWords = (str) => {
  return str.replace(/\w{5,}/g, function(w) { 
    return w.split('').reverse().join(''); });
}

But not all clever solutions are good to go on production. It does fit this problem but difficult to mutate or reuse the technique if problem changes. The next one's better.

const revWords = (str, n) => {
  return str.split(' ').map(function (word) {
    return (word.length >= n) ? 
    word.split('').reverse().join('') : word;
  }).join(' ');
}

Top comments (5)

Julian Pufler • Jul 12 '20

If I understood the problem correctly, why don't you just do this:

const toReverse = 'abc def ghi'
const reversed = toReverse.split('').reverse().join('')

Parwinder 👨🏻‍💻 • Jul 12 '20

Julian, I believe Divyajyoti is missing a key part of the description (from my understanding). She wants to reverse the words in a string, not the whole string.

This is what your example produces:

const toReverse = 'hello bella cause birds fancy';
const reversed = toReverse.split('').reverse().join('');
console.log(reversed);
// "ycnaf sdrib esuac alleb olleh"

This is what her solution produces:

const revWords = (str, n) => {
  return str.split(' ').map(function (word) {
    return (word.length >= n) ? 
    word.split('').reverse().join('') : word;
  }).join(' ');
}

console.log(revWords("hello bella cause birds fancy", 5));
// olleh alleb esuac sdrib ycnaf

That being said, I feel the original solution could be improved. It could be simplified a lot. There is no need to know word length.

const reverseWordsInPlace = (input) => {
    return input.split(" ").map(
     word => word.split("").reverse().join("")
    ).join(" ");
}

console.log(reverseWordsInPlace("hello bella cause birds fancy car is a bmw"));
// "olleh alleb esuac sdrib ycnaf rac si a wmb"
// used an input with different word length to prove we shouldn't care about word length

Divyajyoti Ukirde • Jul 13 '20 • Edited

If the question has word length specifically mentioned then you need to apply my solution. I have made the text bold, to avoid confusion. The n there is word-length basically and only those words need to be reversed that satisfy the word-length condition.

Parwinder 👨🏻‍💻 • Jul 13 '20

Ah, you only want n length or above words in a string reversed in place. Now it makes more sense. Danke!

Julian Pufler • Jul 12 '20

Oh, yeah I totally missed that because I was on mobile. Thanks for clearing it up, your solution is probably the shortest you can do! 👍

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Easy peasy reverse words

Top comments (5)

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