date_format
Description
Sets the date format that is used to parse data from a data set and to send dates back to the server
date_format: string
Example
gantt.config.date_format = "%Y-%m-%d %H:%i";
...
gantt.init("gantt_here");
gantt.load("/data/tasks");
Default value: "%d-%m-%Y %H:%i"
Details
This config value is used to generate parse_date and format_date template functions. If you want to use a custom format, you can either change this config, or redefine parse_date and format_date templates directly.
Loading dates in ISO format
Since v9.1.3, Gantt automatically detects and parses ISO 8601 date strings. The date_format config is not needed for ISO strings - they are recognized and parsed directly.
When ISO dates are detected on input, they are serialized back as ISO strings automatically when passed to the DataProcessor. Date-only strings (e.g., "2026-01-06") are serialized back as date-only strings, preserving the original format.
The date_format config still applies to non-ISO date strings.
In versions before v9.1.3, ISO dates were not detected automatically. If you are using an older version, you need to override parse_date and format_date templates to handle ISO strings:
gantt.templates.parse_date = function(date) {
return new Date(date);
};
gantt.templates.format_date = function(date) {
return date.toISOString();
};
For more details, see Loading dates in ISO format.
Changing the date format dynamically
If you need to change the date format dynamically, it is necessary to modify the parse_date template in the following way:
const cfg = gantt.config;
const strToDate = gantt.date.str_to_date(cfg.date_format, cfg.server_utc);
gantt.templates.parse_date = function(date){
return strToDate (date);
};