Subcomponents or neater way to pass lots of params to a component



I made a choice to use Emblem early on, so appologies as I can’t show it as Handlebars. Basically this is what I wanted to do:

pie-chart source="/data.json"
  .param data-name="Param 1"
  .param data-name="Param 2"

The pie-chart component makes a JSON request and displays the result in a chart. My issue is that I don’t have access to the child elements for the component before it’s rendered, obviously. So is there another way to do this? I don’t want to place the params in the URL or as component params, as it gets unwieldly.