How to append (connect) strings to construct a new string?

Question

I have a array of strings:

str[1]='apple';
str[2]='orange';
str[3]='banana';
//...many of these items

Then, I would like to construct a string variable which looks like var mystr='apple,orange,banana,...', I tried the following way:

var mystr='';
for(var i=0; i<str.length; i++){
  mystr=mystr+","+str[i];
}

Which is of course not what I want, is there any efficient way to connect all this str[i] with comma?

Answer 1

just use the built-in join function.

str.join(',');

Answer 2

Check out join function

var str = [];
str[0]='apple';
str[1]='orange';
str[2]='banana';

console.log(str.join(','));

would output:

apple,orange,banana