code: function(line) {
          var newLine;
  
          // ex: [foo <- 1,2,3]
          // [        opening array
          //   (.*)   $1 array to concat into
          //   (<-)   $2
          //   (.*)   $3 content to be merged
          // ]        closing array
          var regexArr = /\[(.*)(\<\-)(.*)\]/;
  
          // ex: {foo <- foo: true, bar: 2}
          // {        opening object
          //   (.*)   $1 obj to merge into
          //   (<-)   $2
          //   (.*)   $3 content to be merged
          // }        closing object
          var regexObj = /\{(.*)(\<\-)(.*)\}/;
  
          newLine = line.replace(regexArr, function($0, $1, $2, $3) {
              return $1.trim() + '.concat([' + $3 + ']);';
          });
  
          return newLine.replace(regexObj, function($0, $1, $2, $3) {
              return $1.trim() + '.merge({' + $3 + '});';
          });
      }
docs: merges immutable objects or arrays together returns String a -> String b