Support collections of hybrid types

[loic-yvonnet]

Currently, a collection can contain members of a single type. The type of the first member overwrites others.

Let’s say we have a resource /cars/ which is a Collection of cars. There are 2 subtypes of cars in the Web API: sandero and audi. The representation sent back from GET /cars/ contains both a sandero and an audi (in this order). Currently, requesting the available operations on the audi will result in showing the sandero’s operations.

The reason is that the DOM layout is expected to contain 2 levels of spans (cf. line 246 element.parent().parent() in hydra.js) to return the right type associated with the selection. Arrays (which are used for collections), contrary to objects, have only one level of span around them.

A fix could consist simply in adding the additional required span level for arrays (line 300).

      if (_.isArray(data)) {
        result += '[<br>' + indent;
        for (i = 0; i < data.length; i++) {
          result += '<span>'; // new line
          result += '  ';
          result += this.renderResponse(data[i], indent + '  ', (i === data.length - 1));
          result += indent;
          result += '</span>'; // new line
        }
        result += ']';
      }