Как токенизировать строку

function tryTokenize(token) { 
      if (token == "put") { 
        return { 
          "IO": "PUT" 
        }; 
      } else if (token == "(") { 
        return { 
          "ROUND_BRACKET_START": "(" 
        }; 
      } else if (token == ")") { 
        return { 
          "ROUND_BRACKET_END": ")" 
        }; 
      } else if (token == "\"") { 
        return { 
          "QUOTE": "\"" 
        }; 
      } 
     
      return false; 
    } 
     
    function lexer(source) { 
      var results = []; 
      var currentStr = ""; 
      var currentToken 
      for (var i = 0; i < source.length; i++) { 
        currentStr += source[i]; 
        currentToken = tryTokenize(currentStr); 
        if (currentToken !== false) { 
        	 
          results.push(currentToken); 
          currentStr = ""; 
        } 
      } 
    	return results; 
    } 
    var source = "put(\"Hello\")"; 
     
     
    console.log(lexer(source));