How to set a String object's string value in JavaScript from within its methods?

why not using concat function? as its already in the string funtion
var x = "Wayne's";
x.concat("World");

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A short answer to my question seems to be that "In JavaScript, strings are immutable objects, which means that the characters within them may not be changed and that any operations on strings actually create new strings."
(ref. http://stackoverflow.com/questions/51185...)

Which probably explains why I cannot prototype it (i.e. add methods that act on and change the string).

However, your suggestion, teddyjas, will indeed work in the specific example I gave. I do not at the moment understand how this relates to the immutability problem, but it might be another question.
Since so much time has passed I'll award the points and close the question.

Try defining a new object that contains the immutable string object. I like the name 'gstring' for general string (also a bit of a pun). You can then replace the internal reference at will. You could also use an array to represent each character of the string for maximal manipulation. All you then need is a to_string() method to make the final conversion.

You can have your cake and eat it too!

Simply encapsulate the string inside an object. Below is an example:

function gstring(init) // general string object
{
// constructor
var s=init;

// accessor methods
this.toString=function(){return s;};
this.to_s=function(){return s;};
this.to_n=function(){return parseFloat(s);};
this.size=function(){return s.length;};
this.clone=function(){return new gstring(s);};

// modifies self and returns this
this.zap=function(){s=""; return this;};
this.concat=function(p){s+=p; return this;};
this.init=function(p){s=p; return this;};

// removes found section, returns left, and retains right
this.parse=function(rgx)
{
var pos=s.search(rgx);
if(pos < 0) // not found, return entire object
{
this.found="";
var rtn=gstring.new(s);
s="";
return rtn;
}
var ary=s.match(rgx);
var left=s.substr(0,pos);
this.found=ary[0]; // preserve a copy
s=s.substring(pos+this.found.length);
return new gstring(left);
};
}

// optional constructor:
gstring.new=function(init){return new gstring(init);}

/////////////\\\\\\\\\\\\\\

now to create one you can do this:

var myString = gstring.new("wow, now I have a string!");

my parse method looks for a token to split the string, keeps the right-hand side in the object, returns the left-side of the token, and allows you to access what token was found (in case you use an rxg).

example:

var left=myString.parse(','); // left == 'wow'
alert('>>'+myString); // == '>> now I have a string!'

Notice that gstring (pun intended) can be used in an expression as shown above. You can add more methods as needed, or copy the ones from javascript's string. As for the method above, concatenation is one of the methods.

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