javascript - 字符串中的第一个字母增加，最后一个字母减少

Question

我正在尝试创建一个简单的编码器，其中每个单词的第一个字母成为它的后继字母 (A = B)，最后一个字母成为它的前导字母 (B = A)。

像这样:

KEY: The first letter goes up, the last letter goes backwards.
</p>

If it is the first letter in the string, <span style='color: red;'>x</span> should be converted to <span style='color: blue;'>y</span>, as seen below:
</p>
<span style='color: red;'>Aa</span> = <span style='color: blue;'>Bb</span>
</p>
<span style='color: red;'>Bb</span> = <span style='color: blue;'>Cc</span>
</p>
<span style='color: red;'>Cc</span> = <span style='color: blue;'>Dd</span>
</p>
<span style='color: red;'>Dd</span> = <span style='color: blue;'>Ee</span>
</p>
and so on....
</p>
If it is the last letter in the string, <span style='color: lightgreen;'>x</span> should be converted to <span style='color: orange;'>y</span>, as seen below:
</p>
<span style='color: lightgreen;'>Aa</span> = <span style='color: orange;'>Zz</span>
</p>
<span style='color: lightgreen;'>Bb</span> = <span style='color: orange;'>Aa</span>
</p>
<span style='color: lightgreen;'>Cc</span> = <span style='color: orange;'>Bb</span>
</p>
<span style='color: lightgreen;'>Dd</span> = <span style='color: orange;'>Cc</span>
</p>
and so on....
</p>

<div class="encode">
  The fox jumped over the dog. = Uhd gow kumpec pveq uhd eoh.
</div>

我正在尝试使用 javaScript 来完成此操作，但是，我愿意使用任何可以实现此目的的语言。

这段代码是我正在寻找的要点，但我需要定位 div 中每个单词的第一个和最后一个字母:

var strRandomString = "I have 2 apples and 6 oranges and 3 grapes";
strRandomString.replace(/apples|oranges/g, function(m) {
    // `m` is a matched string.
    return m === 'apples' ? 'oranges' : 'apples';
})
// => "I have 2 oranges and 6 apples and 3 grapes"

不幸的是，我没有任何实际的示例 javaScript 代码(但上面的代码可以算作一次尝试，一次失败的尝试)，因为我已经研究了大约半个小时，但找不到可行的解决方案。

我搜索了以下线程以寻求帮助:

https://codereview.stackexchange.com/questions/32620/replacing-every-letter-in-a-string-with-the-letter-following-it-in-the-alphabet

Promoting letters in a string to previous letter in java

https://coderanch.com/t/552363/java/Replacing-characters-string

http://www.dreamincode.net/forums/topic/326746-question-shifting-characters-to-the-next-letter-in-the-alphabet/

https://www.extendoffice.com/documents/excel/4027-excel-increase-letter-by-one.html (是的，我非常绝望，我正要使用 excel)。

Answer 1

这适用于单词，也适用于短语

function transform(phrase)
{ var i,last,letters,words=phrase.split(/\s+/);
  for(i=0;i<words.length;i++)
  { letters=words[i].split('');
    last=letters.length-1;
    letters[0]=letters[0].charCodeAt(0)<122?String.fromCharCode(letters[0].charCodeAt(0)+1):'a';
    letters[last]=97<letters[last].charCodeAt(0)?String.fromCharCode(letters[last].charCodeAt(0)-1):'z';
    words[i]=letters.join('');
  }
  return words.join(' ');
}

console.log(transform('apple zebra variables'));
//outputs 'bppld aebrz wariabler'