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JavaScript string concatenation
does javascript have a built in stringbuilder class?
As it's known when we do str = str + "123" a new string is created. If we have a large number of concatenations it can be rather expensive. Is there a simple way to implement a StringBuilder in JavaScript?
You can push the parts into an array, and then join it:
var builder = []
builder.push( "some", "123" );
builder.push( "content" );
var str = builder.join("");
This SO question explains it in detail, see also this class
var str = ['some', '123', 'content'].join(''); (usually with line breaks between items)Traditional concatenation in JavaScript is optimal if the strings are static.
var foo = 'a' + 'b' + 'c' + 'd';
this is true in most browsers. string-concatenation
If the strings may be variable according to the program either method is equally efficient.
var foo = ""+Math.random() + Math.random() + Math.random() + Math.random();
var foo = [Math.random(), Math.random(), Math.random(), Math.random()].join('');
the differences are not too great between browsers, but the traditional way seems a little better string-random-concatenation
I think, it's never really simple to implement a StringBuilder that is faster than normal string concatenations. And that's obviously the reason for the Builder.
Fill an array an if it's full convert it to string.
StringBuilderlike in C#