Allow displaying a different field that the linked valueField in Relation widget

[medfreeman]

- Do you want to request a feature or report a bug?

Feature
Needs #597 first.

- What is the current behavior?

The Relation widget allows linking to another collection item.
The searchFields property defines in what item fields netlify will look for the user provided string.
The valueField property defines what value will be stored in the relation field, thus creating a link between the current item and searched item.

- Context

I created a menus collection that can link to pages collection items on two levels:

  - name: "menus"
    label: "Menu"
    editor:
      preview: false
    folder: "content/menus"
    create: true
    widget: "object"
    fields:
      - { label: "Title", name: "title", widget: "string" }
      - label: "Items"
        name: "items"
        widget: "list"
        fields:
          - { label: "Page", name: "page", widget: "relation", collection: "pages", searchFields: ["title", "body"], valueField: "uuid" }
          - label: "Items"
            name: "items"
            widget: "list"
            fields:
              - { label: "Page", name: "page", widget: "relation", collection: "pages", searchFields: ["title", "body"], valueField: "uuid" }

I also created an uuid read-only widget that allows linking to a page by a constant unique per-item field, thus preventing the menu links to break in the case the valueField is set to title and the user changes the page title for example.

- What is the expected behavior?

Add a displayField property that would allow displaying a different field that the linked valueField.

In my above example i would have uuid as valueField and title as displayField.
The user would see the page title as menu entry, but the stored value would be the uuid.

[barthc]

@tomrutgers please confirm this issue is already fixed in #1303 before closing.

[tomrutgers]

Correct. You can now use displayFields: []. It defaults to valueField

[papandreou]

@tomrutgers, displayFields only has an effect on the autocompleter, though, not when a related entry has been selected. This means that a relation to a "id" like field will look user unfriendly most of the time:

... I think this is what the OP means.

Also discussed here: #1982 (comment)

[tomrutgers]

This issue was opened when there wasn't a displayFields property available, so it is a bit different from #1982 I suppose. Since then a displayFields has been added but it has it issues for selection. Would you like to keep both issues open @papandreou?

[papandreou]

@tomrutgers, hmm, I think #1982 covers the remaining bits pretty well, so it's fine that this one is closed. Just wanted to clarify 👍

[tomrutgers]

Agreed 👍
Thanks for your input!