Conditional fields

Use a condition to show a field only when it is relevant. For example, show a video URL when an author selects “Video” as the post format. The admin updates immediately as values change.

Set Admin.VisibleWhen to the condition that must be true:

field.Text("videoURL").Admin(field.Admin{
  VisibleWhen: field.Equal(field.Sibling("format"), "video"),
})

Read that expression as: “show videoURL when the format field beside it equals video.”

Show a field when another value matches

This collection reveals videoURL when an author chooses the Video format:

package content

import (
  "github.com/riducms/ridu"
  "github.com/riducms/ridu/field"
)

var Posts = ridu.Collection{
  Slug: "posts",
  Fields: field.Fields{
    field.Text("title").Required(),
    field.Select("format", "article", "video").Default("article"),
    field.Text("videoURL").Admin(field.Admin{
      VisibleWhen: field.Equal(field.Sibling("format"), "video"),
    }),
  },
}

Use values from groups and repeated rows

field.Sibling("name") reads a field beside the one being shown:

• A root field reads another root field.
• A field inside a Group reads from that Group.
• A field inside an Array or Block reads from its own row, not another row.
• A sibling path can descend through non-repeating Groups, such as settings.kind.
• A path cannot cross through an Array or Blocks list. Ridu reports an error when you start the application.

The following condition is attached to answers.explanation. Each answer reads its own settings.kind, while field.Root("archived") always reads the root archived field:

var Questions = ridu.Collection{
  Slug: "questions",
  Fields: field.Fields{
    field.Checkbox("archived").Default(false),
    field.Array("answers", field.Fields{
      field.Group("settings", field.Fields{
        field.Select("kind", "lesson", "question", "note"),
      }),
      field.Textarea("explanation").Admin(field.Admin{
        VisibleWhen: field.All(
          field.OneOf(field.Sibling("settings.kind"), "lesson", "question"),
          field.Not(field.Equal(field.Root("archived"), true)),
        ),
      }),
    }),
  },
}

At the document root, Sibling("status") and Root("status") read the same value. Prefer Sibling when the rule should remain relative if those fields later move together into a Group or repeated row. Use Root when the rule should always read a top-level field. Use stored field names with dots for nested objects. Layout fields such as Row and Collapsible do not add a part to the path.

Compare and combine values

Use a comparison value that matches the field type: a string for text or choices, a boolean for a checkbox, or a number for a number field. Ridu checks the condition when the application starts.

Strings, booleans, and numbers are supported. For example:

field.Equal(field.Sibling("featured"), true)
field.NotEqual(field.Sibling("score"), 0)
field.OneOf(field.Sibling("status"), "draft", "review")

Use field.All when every condition must match, field.Any when at least one must match, and field.Not to reverse a condition. All and Any require at least two conditions; Not takes one. The example above combines the answer type with the document’s archived setting.

Validate hidden fields and protect their values

Hiding a field keeps its existing value. Changing the post format from Video to Article, for example, does not delete an entered video URL. The field can still be submitted through REST, the SDK, or the Local API. A visibility condition does not validate data or grant permissions.

Add a server-side rule when you need to enforce a requirement:

See reading sibling values for those contexts and the complete row-scoped field access example.

Troubleshooting

• If a nested condition reads the wrong value, confirm that the controlling field shares the same Group, Array row, or Block with the field being shown. Use field.Root for a root value.
• If a condition never matches, check that the comparison type matches the referenced field. The boolean true is different from the string "true".
• Use All, Any, and Not in Admin.VisibleWhen to combine conditions.
• If an API caller can still write the hidden field, add field access or a hook. That behavior is intentional.

See field.Sibling, field.Root, field.Admin.VisibleWhen, and field.Equal for their exact signatures.