# Welcome to the Highcharts Gantt JS (gantt) Options Reference

These pages outline the chart configuration options, and the methods and properties of Highcharts objects.

Feel free to search this API through the search bar or the navigation tree in the sidebar.

# chart.allowMutatingData

By default, (because of memory and performance reasons) the chart does not copy the data but keeps it as a reference. In some cases, this might result in mutating the original data source. In order to prevent that, set that property to false. Please note that changing that might decrease performance, especially with bigger sets of data.