Overriding default layout

RichardD2

Link to test case:
https://live.datatables.net/segonewe/1/edit?js,output

Description of problem:
I'm trying to upgrade a large application from v1.10 to v2.1.4, and replace the use of the deprecated dom option with the new layout option.

I've managed to get quite close, but I've run into a strange problem.

I have a default layout which adds a custom feature in the top and bottom. On some pages, I need to override that default layout with a custom layout. But trying to do so results in a weird mix of the two!

Eg:

Default layout:

top: {
    features: [
        {
            pageLength: {}
        },
        {
            div: {
                text: "(custom feature)"
            }
        },
        {
            search: {
                placeholder: "Search"
            }
        }
    ]
}

Overridden layout:

top: {
    features: [
        {
            pageLength: {}
        },
        {
            div: {
                text: "(custom feature 1)"
            }
        },
        {
            div: {
                text: "(custom feature 2)"
            }
        },
        {
            search: {
                placeholder: "Search"
            }
        }
    ]
}

Expected result:
* Page length
* Custom feature 1
* Custom feature 2
* Search

Actual result:
* Page length
* Custom feature 1
* Search
* Custom feature 2
* Search

Why am I getting an extra "search" feature injected into the layout? Is there an easy way to fix this?

RichardD2

I think I've found a rather hacky workaround: rather than using top in the page-specific setup, I set top to null and use top1 instead.

new DataTable("#example", {
    layout: {
        top: null,
        top1: {
            ...
        }
    }
});

I'm guessing there's a bug somewhere in the code to merge the table settings with the default settings.

allan

That's an interesting one - thanks for posting this. The issue is that the defaults are merged with the per table options as a deep merge - not a shallow one. In this case you what a shallow copy of the position attributes.

I need to have a bit of a think about this, as there are cases where one might want (and expect) a deep copy.

For the moment, your workaround is a good one.

Allan