> For the complete documentation index, see [llms.txt](https://sway-technologies.gitbook.io/sway-charts-pro-scripts-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sway-technologies.gitbook.io/sway-charts-pro-scripts-documentation/sway-charts-pro-user-defined-indicators/changes-to-the-chart-or-parameters.md).

# Changes to the chart or parameters

If there is a change to the chart, such as a switch of timeframe, or a change by the user to your user-defined settings, then the chart will always make your UDI recalculate all its data by issuing a call to UDI.onCalculate().

However, if you need to take special, extra action when these values/settings change, then you can implement the optional functions UDI.onContextChange() and UDI.onParameterChange()