Can someone explain this .replace logic?

Question

I'm trying to adapt a script that converts ALL CAPS text in a text area to lowercase (with the first word capitalized). Part of my issue was resolved here.

It works, but... my textarea text is in the following format: dash, space, then TEXT.

- TEXT1
- TEXT2
- TEXT3

The script I have , and the .replace logic, do not account for the "-" and space, and it does not account for each line separately.

here is the script:

$(window).load(function(){
$('#normalize').click(function capitalizeSentences(){

var capText = $("#finaltext").val();
capText = capText.toLowerCase();

capText = capText.replace(/\.\n/g,". [-<br>-]. ");
capText = capText.replace(/\.\s\n/g,". [-<br>-]. ");
var wordSplit = '. ';

var wordArray = capText.split(wordSplit);

var numWords = wordArray.length;

for(x=0;x<numWords;x++) {

    wordArray[x] = wordArray[x].replace(wordArray[x].charAt(0),wordArray[x].charAt(0).toUpperCase());

        if(x==0) {
            capText = wordArray[x]+". ";
        }else if(x != numWords -1){
            capText = capText+wordArray[x]+". ";
        }else if(x == numWords -1){
            capText = capText+wordArray[x];
        }               
}
capText = capText.replace(/\[-<br>-\]\.\s/g,"\n");
capText = capText.replace(/\si\s/g," I ");  
$("#finaltext").val(capText);
});
});

I don't follow the syntax or logic in the .replace() portions. Is there a primer on how the logic is constructed, or can someone give me a breakdown so I can adapt it more precisely?

Answer 1

Okay, after some reading on RegEx and some trial and error, I have (stumbled) upon the solution to my problem.

I realized that most of the stuff in the script I adapted was irrelevant junk. So I stepped back and took the problem piecemeal.

First, I decided to render all the text in lowercase:

var capText = $('#finaltext').val();
capText=capText.toLowerCase();

then, I needed to use .replace to find all instances of "dash+space+any letter":

.replace(/- ./g,

This will find the one letter after the dash in all instances, then I combine with a function to make uppercase:

.replace(/- ./g, function(c){return c.toUpperCase();});

final code is:

$('#normalize').click(function capitalizeSentences() {
    var capText = $('#finaltext').val();
    capText=capText.toLowerCase();
    capText2 = capText.replace(/- ./g,function(c){ return c.toUpperCase(); });
    $("#finaltext").val(capText2);
});

See here - http://jsfiddle.net/fDy6K/

Answer 2

What you are seeing in the code is the literal format for regular expressions. In the literal format you enclose your expressions inside slashes (/), and optionally add flags after the second slash.

Within your specific code example:

capText.replace(/\.\n/g,". [-<br>-]. ");

Is equivalent to

capText.replace(new RegExp("\.\n", "g"),". [-<br>-]. ");