Incorrect dasharray value

[3zzy]

cartocss = "{ line-color: #7B00B4; line-width: 1; line-opacity: 0.7; line-dasharray: 4,2; }";
shader = new carto.RendererJS().render(cartocss),
style = shader.layers[0].getStyle({ property: 1 }, { zoom: zoom });

console.log({shader, style}); 

Value returned for the dasharray is just 4 instead of 4,2. Am I missing something?

Also, in the example on the homepage, the getStyle method takes the first argument { property: 1 } what does that mean?

Thanks