Data type for dashStyle in LineChart

[kum-deepak]

Currently, the API documentation (http://dc-js.github.io/dc.js/docs/html/LineChart.html#dashStyle__anchor) suggests it to be an array of numbers. However, the see also link https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/stroke-dasharray suggests it to be a string. It currently works because when setting a non-string value (https://developer.mozilla.org/en-US/docs/Web/API/Element/setAttribute), it is converted to a string.

We should update this library to use string with backward compatibility.

[kum-deepak]

Also the example

// create a Dash Dot Dot Dot
chart.dashStyle([3,1,1,1]);

it will generate a Dash Dot.

[gordonwoodhull]

Agree this shouldn't happen by accident, and the example is wrong.

I would suggest permanently accepting either string or an array, and explicitly converting the array with .join(',') – the array form is more useful than the string form.

I'm indifferent whether conversion happens on set or on use. I doubt the getter is used much, so it should be ok to always return string.