Grunt task to copy bower components to a static/public web directory. Organises based on file extension. Uses the "bower" cli, so no need to install the entire bower module.

Gruntfile.js

module.exports = function (grunt) {

  var path = require('path');

  grunt.initConfig({
    pkg   : grunt.file.readJSON('package.json')
  , bower : {
      all : {
        dest : 'static'
      }
    }
  });

  grunt.registerMultiTask('bower', 'Copy bower components', function () {
    var done  = this.async()
      , dest  = this.data.dest
      , bower = {
          cmd  : 'bower'
        , args : ['list', '--paths']
        };

    if (!grunt.file.isDir(dest)) {
      grunt.verbose.writeln('Creating dest dir: ' + dest);
      grunt.file.mkdir(dest);
    }

    grunt.util.spawn(bower, _copy);

    function _copy (err, result, code) {
      var components
        , files
        , name;

      if (err || code) {
        grunt.log.error("`bower list --paths' command failed to run:");
        grunt.log.error(err.message || err);
        grunt.log.error('Exit code: ' + code);
        done(false);
        return;
      }

      try {
        components = JSON.parse(result)
      } catch (e) {
        grunt.log.error("Failed to parse `bower list --paths' output:");
        grunt.log.error(e.message || e);
        done(false);
        return;
      }

      for (name in components) {
        files = components[name];
        files = grunt.util.kindOf(files) == 'string' ? [files] : files;
        files.forEach(function (file) {
          var basename = path.basename(file)
            , extname  = path.extname(file).slice(1)
            , destname = path.join(dest, extname, basename);
          grunt.file.copy(file, destname);
          grunt.log.writeln(file + ' -> ' + destname.cyan);
        });
      }

      done();
    }
  });
};