Question

Is “return this” necessary at the end of every method within a Backbone view?

render: function() {
this.editElem();
// I realize it wouldn't be necessary here, but...
},

renderElem: function() {
this.$el.addClass('foobar');
return this // is this one necessary?
},

EDIT
What about this example?

render: function() {
this.editElem();
},

renderElem: function() {
this.$el.addClass('foobar');
return this;
},

Answer 1

To quote what the official documentation says

A good convention is to return this at the end of render to enable chained calls.

So no it’s not necessary but it’s probably a good idea.

In general you will see it in methods that modify/render the view’s el, by returning this in one of those methods you are making it easier to access the view’s el, so that you can now do something like

$("#somelist").append(myview.render().el);

instead of doing it in two lines like

myview.render();
$("#somelist").append(myview.el);