What's :locals for in render in rails?

Question

Here is the API definition for render:

render(options = {}, locals = {}, &block)

Returns the result of a render that’s dictated by the options hash. The primary options are:

    :partial - See ActionView::Partials.

    :file - Renders an explicit template file (this used to be the old default), add :locals to pass in those.

    :inline - Renders an inline template similar to how it’s done in the controller.

    :text - Renders the text passed in out.

There is no explanation about what's the purpose of locals here? What's locals for?

Thanks.

Answer 1

To pass local variables to the partial template, as opposed to controller instance variables.

See Section 3.4.4, Passing Local Variables in the Layouts and Rendering Guide.