Color by legend is broken for numeric traits

[huddlej]

Selecting a color by option that has numerical values produces an error that "something has gone wrong". For example, selecting "Age" in the novel coronavirus build (https://nextstrain.org/ncov?c=age) produces this output:

Using git bisect, I tracked this error down to the truncation of legend labels using the substring method.

I'm not familiar enough with React to implement a solution here, but it seems like we need to check the type of the label prior to applying substring.

[joverlee521]

Thanks for tracking this down! I think we can throw String() around the label to convert everything to a string before calling substring

[tsibley]

Yeah, this is a JavaScript type thing. Strings have a substring method, but Numbers don't. I expect a forced conversion to string is needed. There are many ways to format a Number, but label + "" might be enough.

Edit: or what Jover said!

[huddlej]

Ok, I actually was able to fix the issue with an explicit check for type (5f4a6d7), but if y'all prefer casting to string for everything, that's fine, too.

[tsibley]

Thanks! I think that type check is fine. The label will be cast to a string anyway as part of the template interpolation, but I think it does make more sense not to apply character-length limits to a numeric value.