code: function find(map, name) {
  	name = name.toLowerCase();
  	for (const key in map) {
  		if (key.toLowerCase() === name) {
  			return key;
  		}
  	}
  	return undefined;
  }
docs: Find the key in the map object given a header name.
  
  Returns undefined if not found.
  
  @param   String  name  Header name
  @return  String|Undefined