Ext.ux.StringBuilder

[evant]

Hi all, I made this for a project, thought someone might find it useful. It's not thoroughly tested, but it should come in handy:

For those not familiar, a string builder is an object used to concatenate strings.
Advantages of using this object:
1) Your code may appear cleaner (subject to debate ;))


var sb = new Ext.ux.StringBuilder();
sb.append('string1');
sb.append('string2');
Ext.get('foo').update(sb.toString()); //prints 'string1string2'

2) Supports strings, arrays and objects


var sb = new Ext.ux.StringBuilder('foo');
var other = new Ext.ux.StringBuilder();
other.append(sb);
other.append(['1', '2', '3']);
other.append('bar');
Ext.get('foo').update(other.toString()); //prints 'foo123bar'

3) Is optimized for particular browsers (Thanks Jack)
4) Supports chaining


var sb = new Ext.ux.StringBuilder();
sb.append('a').append('b').append('c').append(['1','2','3']);
Ext.get('foo').update(sb.toString()); //prints 'abc123'


Also, thanks to Animal for pointing out how to do the private functions. Cheers



Ext.namespace('Ext.ux');

Ext.ux.StringBuilder = function(start)
{
this.builder = '';
this.items = [];
this.append(start);
};

Ext.ux.StringBuilder.prototype = (function()
{
function appendString(s)
{
if (Ext.isIE)
this.items.push(s);
else
this.builder += s;
}

function appendArray(a)
{
Ext.each(a, function(el)
{
this.append(el);
}, this);
}

function appendObject(o)
{
if (o.toString)
appendString.call(this, o.toString());
}

return {
append: function(o)
{
if (o)
{
if (typeof o == 'string')
appendString.call(this, o);
else if (o instanceof Array)
appendArray.call(this, o);
else
appendObject.call(this, o);
}
return this;
},

toString: function()
{
return Ext.isIE ? this.items.join('') : this.builder;
},

clear: function()
{
this.items = [];
builder = '';
}
}
})();


Enjoy.

[Nullity]

How about a description of what it does?

EDIT: Sorry if that sounded harsh... I can figure out what it does easy enough by looking over the code, but others might not want to take the time to do so (even though it's not that difficult to follow)

[Animal]

If you want private functions, try



Ext.ux.StringBuilder = function(start) {
this.items = [];
this.append(start);
};

Ext.ux.StringBuilder.prototype = (function() {
function appendString(s) {
this.items.push(s);
}

function appendArray(a) {
Ext.each(a, function(el) {
this.append(el);
}, this);
}

function appendObject(o) {
if (o.toString)
this._appendString(o.toString());
}

return {
append: function(o) {
if (o) {
if (typeof o == 'string')
appendString.call(this, o);
else if (o instanceof Array)
appendArray.call(this, o);
else
appendObject.call(this, o);
}
},

toString: function() {
return this.items.join('');
},

clear: function() {
this.items = [];
}
}
})();

[jack.slocum]

A very useful class. You may want to consider using + instead of the array/join for Firefox since it has better performance.

[evant]

Thanks guys. I made updates as per your suggestions.

[brian.moeskau]

I'm getting Java/C# flashbacks... ;) Nice class, very useful.

[jack.slocum]

Here's an alternate, more optimized version. While it's not possible to keep performance the same as native string building (especially in Firefox), reducing function calls is important. I also added something I always wished the Java StringBuilder had (which .Net does), a format() function. Instead of processing arrays, append and the constructor take multi args like the template class.

The code is branched at definition time for performance as well. At about 1k it's not bad.



if(Ext.isIE){
Ext.ux.StringBuilder = function(/* multi args */){
this.buffer = [];
if(arguments.length > 0){
this.append.apply(this, arguments);
}
};
Ext.ux.StringBuilder.prototype = {
append : function(/* multi args */){
this.buffer.push.apply(this.buffer, arguments);
},
format : function(format, arg1, arg2, etc){
this.buffer.push(String.format.apply(String, arguments));
},
clear: function(){
this.buffer = [];
},
toString : function(){
return this.buffer.join('');
}
};
}else{
Ext.ux.StringBuilder = function(/* multi args */){
if(arguments.length > 0){
this.buffer = Array.prototype.join.call(arguments, '');
}else{
this.buffer = '';
}
};
Ext.ux.StringBuilder.prototype = {
append : function(s /* multi args */){
if(arguments.length > 1){
this.buffer += Array.prototype.join.call(arguments, '');
}else{
this.buffer += s;
}
},
format : function(format, arg1, arg2, etc){
this.buffer += String.format.apply(String, arguments);
},
clear: function(){
this.buffer = '';
},
toString : function(){
return this.buffer;
}
};
}