Does anyone know if there is a way to adjust the default zoom used on trading view lightweight charts when double-clicking the x-axis? To my knowledge, double-clicking evokes resetTimeScale but there doesn't seem to be any way to set which value is used as default.
The default zoom is determined by the barSpacing property of the time scale options.
You can calculate what the barSpacing is for the current state of a chart by using the getVisibleLogicalRange method on the time scale API and the width of the time scale.
For example:
const visibleLogicalRange = chart.timeScale().getVisibleLogicalRange();
const currentBarSpacing = chart.timeScale().width() / (visibleLogicalRange.to - visibleLogicalRange.from);
// change the current barSpacing
chart.timeScale().applyOptions({
barSpacing: 12, // default is 6
})