how to interchange uppercase and lowercase letters in javascript?

Question

My program must change the case of my word on UpperCase or LowerCase.

Example:

word: "cAPS"

solution: "Caps"

All good, but.

My program works well with one word.

The program checks case of my word by two first symbols(Uppercase or Lower case) But when deal going to sentence I have a problem.

I do not understand, how method I must use. Maybe need to use an array or cycle to doing this?

My problem:

word: "wHY DO wE NEED cAPS lOCK?"

Code of my program:

let newWord = 'cAPS'
word = newWord

if (word.length > 1) {
  var lengthWord = word.length
  if (word.substring(1) == word.toUpperCase().substring(1)) {
    newWord = word.toUpperCase(0, 1).substring(0, 1) +
      word.toLowerCase().substring(1)
    console.log(newWord)
  } else if (word.substring(0) == word.toUpperCase().substring(0)) {
    newWord = word.toLowerCase().substring(0)
    console.log(newWord)
  } else if (word.substring(0, 1) == word.toUpperCase().substring(0, 1)) {
    newWord = word
    console.log(newWord)
  }

}

What is the result supposed to look like? from: "wHY DO wE NEED cAPS lOCK?") to what? — jmrker, Mar 29 '21 at 19:54
Please read [ask], especially the section titled "Write a title that summarizes the question". — Heretic Monkey, Mar 29 '21 at 19:55
Seems similar: https://stackoverflow.com/questions/24471618/swap-case-on-javascript — Sash Sinha, Mar 29 '21 at 19:55

score 0 · Answer 1 · answered Mar 29 '21 at 19:56

0

Do you mean something like this?

let s = "wHY DO wE NEED cAPS lOCK?" ;

let finalS = s.split(' ').reduce((result,word)=>{
   let cleanWord = [...word].map((char,index)=>index===0 ? char.toUpperCase() : char.toLowerCase() ).join('');
   return `${result} ${cleanWord}`
},'');

console.log(finalS);

answered Mar 29 '21 at 19:56

Vahid Alimohamadi

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Yes, that it !!!! – Dan Mar 29 '21 at 19:58
Thank you !!!!!!!!!!!!! – Dan Mar 29 '21 at 20:01

score 0 · Answer 2 · answered Mar 29 '21 at 19:56

Solution 1: Capitalize first letter of every word

word = newWord.split(' ').map(innerWord => `${innerWord[0].toUpperCase()}${innerWord.split('').slice(1).join('')}`);

Solution 2: Capitalize only the first letter of a set of words

word = `${newWord[0].toUpperCase()}${newWord.split('').slice(1).join('')}`

score 0 · Answer 3 · answered Mar 29 '21 at 20:29

Its Simple and easy way convert string UpperCase of each word .

var mystring = "wHY DO wE NEED cAPS lOCK"
var mystring_split = mystring.split(" ")
complete = []

mystring_split.forEach(myFunction);
 function myFunction(item, index) {
   word= item
  if (word.length > 1)
{
var lengthWord = word.length
if (word.substring(1) == word.toUpperCase().substring(1)) {
   newWord = word.toUpperCase(0, 1).substring(0, 1) + 
   word.toLowerCase().substring(1)
   complete.push(newWord)
}
return complete

}
}

console.log( complete.join(" "))

how to interchange uppercase and lowercase letters in javascript?

3 Answers3

Solution 1: Capitalize first letter of every word

Solution 2: Capitalize only the first letter of a set of words