Remove comma on last element in my array?

Question

If I have an array like ["AAA", "BBB", "CCC"] and what to render to the browser a comma after each one EXCEPT the last one in jquery/JS, how do I do that with the function below? Right now, it adds a comma to all elements in the array that includes the last one, and I don't want it on the last one.

JS

  if(designations) {
        var newLinks = designations.map(function(agentDesignations){
            agentDesignations = agentDesignations.toLowerCase();
            return '<a class = "designation-box" data-toggle = "modal" data-target = "#' + agentDesignations + '-modal" data-value = '+ agentDesignations + '>' + agentDesignations + '</a>' + ',\n'});
        return newLinks.join("\n");
    }

Answer 1

通过使用正则表达式+$来解决问题

return newLinks.join("\n").replace(/,+$/,'');

Answer 2

remove the ",\\n" from the return in the map, and change the last return to newLinks.join(",\\n\\n")

like this:

  if(designations) {
        var newLinks = designations.map(function(agentDesignations){
            agentDesignations = agentDesignations.toLowerCase();
            return '<a class = "designation-box" data-toggle = "modal" data-target = "#' + agentDesignations + '-modal" data-value = '+ agentDesignations + '>' + agentDesignations + '</a>';
        });
        return newLinks.join(",\n\n") + '\n';
    }

there's two "\\n" in the join, because that's what you'd end up with currently

more concisely, I'd code this as follows:

  if(designations) {
        return designations.map(function(agentDesignations){
            agentDesignations = agentDesignations.toLowerCase();
            return '<a class = "designation-box" data-toggle = "modal" data-target = "#' + agentDesignations + '-modal" data-value = '+ agentDesignations + '>' + agentDesignations + '</a>';
        }).join(",\n\n") + '\n';
    }

note: two \\n's vs one \\n's have make no difference on the rendering of the resulting HTML, so the last line can simply be

}).join(",\n") + '\n';

or even

}).join(", "); //  note the SPACE, it does make a difference