marko/src/defineRenderer.js

var marko = require("../");

function defineRenderer(def) {
  var template = def.template;
  var getTemplateData = def.getTemplateData;
  var renderer = def.renderer;

  if (typeof template === "string") {
    template = marko.load(template);
  }

  var createOut;

  if (template) {
    createOut = template.createOut;
  } else {
    createOut = def.createOut || marko.createOut;
  }

  if (!renderer) {
    // Create a renderer function that takes care of translating
    // the input properties to a view state. Also, this renderer
    // takes care of re-using existing components.
    renderer = function renderer(input, out) {
      var newProps = input;

      if (!newProps) {
        // Make sure we always have a non-null input object
        newProps = {};
      }

      // Use getTemplateData(state, props, out) to get the template
      // data. If that method is not provided then just use the
      // the state (if provided) or the input data.
      var templateData = getTemplateData
        ? getTemplateData(newProps, out)
        : newProps;

      // Render the template associated with the component using the final template
      // data that we constructed
      template.render(templateData, out);
    };
  }

  renderer.render = function(input) {
    var out = createOut();
    renderer(input, out);
    return out.end();
  };

  return renderer;
}

module.exports = defineRenderer;