{% include %} tag accepts variable

if that variable is an object with `render()` it is assumed
to be a template.

see django/django@5cdacbd

docs/tags.md

@@ -428,6 +428,10 @@ the variable ``template_name``:
 
     {% include template_name %}
 
+The variable may also be an object with a `render()` method that
+accepts a context. This allows you to reference a compiled `Template` in
+your context.
+
 An included template is rendered with the context of the template that's
 including it. This example produces the output ``"Hello, John"``:
 

lib/tag/loader.js

@@ -16,11 +16,14 @@ IncludeNode.prototype.getByType = Node.prototype.getByType;
 
 IncludeNode.prototype.render = function(context) {
    if (typeof(this.templatePath) === 'string') {
-      var templateName = this.templatePath;
+      var template = this.templatePath;
    } else {
-      var templateName = this.templatePath.resolve(context);
+      var template = this.templatePath.resolve(context);
+   }
+   // does this quack like a Template?
+   if (typeof(template.render) !== 'function') {
+      template = this.env.getTemplate(template);
    }
-   var template = this.env.getTemplate(templateName);
    // render
    var values = {};
    for (var key in this.extraContext) {

test/basic.js

@@ -44,6 +44,16 @@ var TestObj = function() {
       return this;
 }
 
+exports.testIncludeTemplateArgument = function() {
+      // any object having render() can be included as template
+      var ctx = {
+            tmpl: new Template('This worked!')
+      };
+      var outerTmpl = new Template('{% include tmpl %}');
+      var output = outerTmpl.render(ctx);
+      assert.equal(output, 'This worked!');
+
+}
 exports.testBasic = function() {
 
       // register fake template loader for `include` testing later on