Create an array of characters from specified range

Question

I read some code where someone did this in Ruby:

puts (\'A\'..\'Z\').to_a.join(\',\')

output:

A,B,C,D,E,F,G,H,I,J,K,L,M,N,O         


        

Answer 1

var chars = [].concat.apply([], Array(26))
              .map(function(_, i) { return String.fromCharCode(i+65); })
              .join();

The .map function could be a function generator that could be used for different character sets.

function charRange(start) {
    var base = start.charCodeAt(0);
    return function(_, i) { return String.fromCharCode(i + base); };
}

And you may also want to create a "full" Array helper.

function fullArray(len) { return [].concat.apply([], Array(len)); }

Then use them like this.

var chars = fullArray(26).map(charRange("A"))
                         .join();