var lineDasharray: List<Double>?

The LineDasharray property

Specifies the lengths of the alternating dashes and gaps that form the dash pattern. The lengths are later scaled by the line width. To convert a dash length to density-independent pixels, multiply the length by the current line width. Note that GeoJSON sources with lineMetrics: true specified won't render dashed lines to the expected scale. Also note that zoom-dependent expressions will be evaluated only at integer zoom levels.