How inefficient is String concatenation in Javascript?

Question

Such as

var myName = 'Bob';
myName += ' is a good name';

For long operations of this, it there a better way to do it? Maybe with a StringBuffer type of structure?

Thanks! :)

Answer 1

The ‘better’ way would be:

var nameparts= ['Bob'];
nameparts.push(' is a good name');
...
nameparts.join('');

However, most modern JavaScript implementations do now detect naïve concatenation and can in many cases optimise it away, because so many people have (alas) written code this way. So in practice the ‘good’ method won't today be as much faster as it once was.