var handlebars = Handlebars.Create();
handlebars.Configuration.UseJson();

[Fact]
public void JsonTestObjects()
{
    var model = JsonDocument.Parse("{\"Key1\": \"Val1\", \"Key2\": \"Val2\"}");
    var source = "{{#each this}}{{@key}}{{@value}}{{/each}}";
    var handlebars = Handlebars.Create();
    handlebars.Configuration.UseJson();
    var template = handlebars.Compile(source);
    var output = template(model);
    Assert.Equal("Key1Val1Key2Val2", output);
}