dianping/cat · error · Error

Invalid date format.

Error message

Invalid date format.

What it means

datepicker's DPGlobal.parseFormat splits the format string into separators and date parts using the validParts regex (dd, d, DD, mm, m, MM, yy, yyyy). If the format contains no recognizable parts at all (parts is null/empty), the format object cannot be built and the constructor throws 'Invalid date format.'. It is thrown from the plugin's internals when it parses the format option or a data-date-format attribute.

Source

Thrown at cat-home/src/main/webapp/assets/js/uncompressed/date-time/bootstrap-datepicker.js:1462

				clsName: 'years',
				navFnc: 'FullYear',
				navStep: 10
		}],
		isLeapYear: function(year){
			return (((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0));
		},
		getDaysInMonth: function(year, month){
			return [31, (DPGlobal.isLeapYear(year) ? 29 : 28), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][month];
		},
		validParts: /dd?|DD?|mm?|MM?|yy(?:yy)?/g,
		nonpunctuation: /[^ -\/:-@\[\u3400-\u9fff-`{-~\t\n\r]+/g,
		parseFormat: function(format){
			// IE treats \0 as a string end in inputs (truncating the value),
			// so it's a bad format delimiter, anyway
			var separators = format.replace(this.validParts, '\0').split('\0'),
				parts = format.match(this.validParts);
			if (!separators || !separators.length || !parts || parts.length === 0){
				throw new Error("Invalid date format.");
			}
			return {separators: separators, parts: parts};
		},
		parseDate: function(date, format, language){
			if (!date)
				return undefined;
			if (date instanceof Date)
				return date;
			if (typeof format === 'string')
				format = DPGlobal.parseFormat(format);
			var part_re = /([\-+]\d+)([dmwy])/,
				parts = date.match(/([\-+]\d+)([dmwy])/g),
				part, dir, i;
			if (/^[\-+]\d+[dmwy]([\s,]+[\-+]\d+[dmwy])*$/.test(date)){
				date = new Date();
				for (i=0; i < parts.length; i++){
					part = part_re.exec(parts[i]);
					dir = parseInt(part[1]);

View on GitHub (pinned to e815e74d4c)

Solutions

1. Use only supported tokens: d, dd, D, DD, m, mm, M, MM, y, yy, yyyy (e.g. 'yyyy-mm-dd', 'dd/mm/yyyy').
2. If the format is dynamic, validate it with /dd?|DD?|mm?|MM?|yy(?:yy)?/ before initializing the picker and fall back to a default.
3. Check data-date-format attributes in markup for the same token rules.

Example fix

// before
$('#dp').datepicker({ format: 'YYYY-MM-DD' }); // throws

// after
$('#dp').datepicker({ format: 'yyyy-mm-dd' });

var VALID_FORMAT = /dd?|DD?|mm?|MM?|yy(?:yy)?/;
function validDateFormat(f) {
  return typeof f === 'string' && VALID_FORMAT.test(f.replace(VALID_FORMAT, '')) !== undefined &&
    (f.match(/dd?|DD?|mm?|MM?|yy(?:yy)?/g) || []).length > 0;
}
var fmt = validDateFormat(userFormat) ? userFormat : 'yyyy-mm-dd';
$('#dp').datepicker({ format: fmt });

function isParsableFormat(f) {
  return typeof f === 'string' && f.length > 0 &&
    /dd?|DD?|mm?|MM?|yy(?:yy)?/.test(f);
}

When it happens

Trigger: Calling $el.datepicker({format: 'YYYY-MM-DD'}) — uppercase YYYY/MM/DD are not valid parts in this version (it expects yyyy); passing an empty format string; passing a format like 'd-mmm-yyyy' (mmm not supported); passing a Date object or non-string where a format is expected.

Common situations: Porting code from another datepicker (e.g. jQuery UI or moment.js style 'YYYY-MM-DD HH:mm') without converting tokens; copy-pasting .NET or Java format strings ('dd/MM/yyyy' works but 'dd-MMM-yy' does not); dynamically building the format from a variable that is occasionally empty.

Related errors

• Must choose at least one picker
• No URL provided.
• You can't provide both 'acceptedFiles' and 'acceptedMimeType
• %sis illegal
• {regex}

AI-assisted analysis of dianping/cat@e815e74d4c (2026-08-14). Data as JSON: /api/errors/207061031b324233. Report an issue: GitHub.