Javascript将字符串转换为ISO日期

Question

i want to parse an Date String into the ISO Format. Sometimes it work sometimes not.

                            //17.08.2016 00:23:51 doesent work
                            //01.08.2016 00:05:32 work
                            var ParsedData = "COPY FROM ABOVE";

                            console.log("#####Start Date converstion########");
                            console.log("BEFORE Parsed Date: -" + ParsedData + "-");
                            tempdate = new Date(ParsedData);
                            console.log("AFTER Parsed Date: " + tempdate);
                            tempdate = tempdate.toISOString();
                            console.log("ISO Parsed Date: " + tempdate);
                          } catch (e) {
                            console.log(e);
                            if (e instanceof TypeError) {
                              //console.log(e);
                            }
                            else if(e instanceof RangeError) {
                              tempdate = ParsedDate
                            }
                            else {
                               console.log("Error not catched: " + e);
                            }
                          }

                          console.log("Parsed Date: " + tempdate);
                          console.log("#####END Date converstion########");

Produces:

Start Date converstion

BEFORE Parsed Date: 17.08.2016 00:23:51 AFTER Parsed Date: Invalid Date Parsed Date: 17.08.2016 00:23:51

END Date converstion Start Date converstion

BEFORE Parsed Date: 01.08.2016 00:19:02 AFTER Parsed Date: Fri Jan 08 2016 00:19:02 GMT+0100 (CET) ISO Parsed Date: 2016-01-07T23:19:02.000Z Parsed Date: 2016-01-07T23:19:02.000Z

END Date converstion

i have no clue why. i hope somebody can tell me why.

Regards

Answer 1

Date.parse

It is not recommended to use Date.parse as until ES5, parsing of strings was entirely implementation dependent. There are still many differences in how different hosts parse date strings, therefore date strings should be manually parsed (a library can help if many different formats are to be accommodated).

An example of parsing the strings yourself.

 var datetimes = ['17.08.2016 00:23:51', '01.08.2016 00:05:32']; datetimes.forEach(function(datetime) { var dateAndTime = datetime.split(' '); var date = dateAndTime[0].split('.').reverse(); // month is zero indexed date[1] -= 1; var time = dateAndTime[1].split(':'); // assuming datetimes are UTC dateAndTime = new Date(Date.UTC.apply(null, date.concat(time))).toISOString(); // if not UTC but local //dateAndTime = new Date(date[0], date[1], date[2], time[0], time[1], time[2]).toISOString(); console.log(dateAndTime); }); 

Alternatively, if the original strings are already UTC then you could just manipulate the strings and not use Date at all.

 var datetimes = ['17.08.2016 00:23:51', '01.08.2016 00:05:32']; datetimes.forEach(function(datetime) { var dateAndTime = datetime.split(' '); var date = dateAndTime[0].split('.').reverse(); dateAndTime = date.join('-') + 'T' + dateAndTime[1] + '.000Z'; console.log(dateAndTime); }); 

Answer 2

Parsing strings with the Date constructor is strongly discouraged (as is using Date.parse as it is equivalent for parsing). The format you're using is not one that is supported by ECMA-262 so parsing is entirely implementation dependent. Even the formats in the language specification are not consistently supported by browsers in use so either use a bespoke function or a library.

Since the date and time does not have any timezone information, it should be treated as local.

Once you've parsed the string to a Date, you can use toISOString to get the required format, noting that it will always return the date and time as UTC.

 /* Parse string in DD.MM.YYYY HH:mm:ss format ** @param {string} s - string to parse ** @returns {Date} if string has invalid date components, ** an invalid Date is returned */ function parseString(s) { var b = s.split(/\\D/); var d = new Date(b[2], --b[1], b[0], b[3], b[4], b[5]); return d && d.getMonth() == b[1] && d.getHours() == b[3] && d.getMinutes() == b[4]? d : new Date(NaN); } console.log(parseString('17.08.2016 00:23:51').toISOString()); console.log(parseString('01.08.2016 00:05:32').toISOString());