如何在定制的聚合物元素中进行宁静的api查询并将其呈现给聚合物dom-repeater？

I am trying to call a restful api from a custom polymer element and print it in a repeating template. I think the problem is to do with the format of the json data received and the dom-repeat not being able to read it properly. I am trying to call a restful api from a custom