All SignalValues emit when a single value is updated

[b0o]

Is this the intended behavior? I would expect a SignalValue to only emit items when it is updated, not when other values in the Signal are updated.

Demo:

2024-04-16_18-41-12_region_re.mp4

local n = require 'nui-components'

local renderer = n.create_renderer {
  width = 60,
  height = 12,
}

local signal = n.create_signal {
  name = '',
  description = '',
}

local body = function()
  return n.rows(
    n.paragraph {
      is_focusable = false,
      lines = signal.name:map(function(name)
        return {
          -- Use math.random so we can see when renders occur:
          n.line(n.text('Name: ', 'Keyword'), name .. ' (' .. math.random(1, 100) .. ')'),
        }
      end),
    },
    n.paragraph {
      is_focusable = false,
      lines = signal.description:map(function(description)
        return {
          -- Use math.random so we can see when renders occur
          n.line(n.text('Description: ', 'Keyword'), description .. ' (' .. math.random(1, 100) .. ')'),
        }
      end),
    },
    n.gap(1),
    n.form(
      { id = 'form' },
      n.text_input {
        autofocus = true,
        max_lines = 1,
        border_label = 'Name',
        on_change = function(val)
          signal.name = val
        end,
      },
      n.text_input {
        max_lines = 1,
        border_label = 'Description',
        on_change = function(val)
          signal.description = val
        end,
      }
    )
  )
end

renderer:render(body)

---

The following patch would make it behave in the way I would expect:

2024-04-16_18-48-14_region_re.mp4

diff --git a/lua/nui-components/signal/init.lua b/lua/nui-components/signal/init.lua
index 9446bd5..f6cdd92 100644
--- a/lua/nui-components/signal/init.lua
+++ b/lua/nui-components/signal/init.lua
@@ -47,7 +47,7 @@ function Signal.create(object)
     end,
     __newindex = function(t, key, value)
       t[self.__index][key] = value
-      self._private.subject(t[self.__index])
+      self._private.subject(t[self.__index], key)
     end,
   })
 
diff --git a/lua/nui-components/signal/value.lua b/lua/nui-components/signal/value.lua
index 90238ae..646166d 100644
--- a/lua/nui-components/signal/value.lua
+++ b/lua/nui-components/signal/value.lua
@@ -10,9 +10,13 @@ function SignalValue.create(subject, key)
     _private = {
       key = key,
       subject = subject,
-      observable = subject:map(function(value)
-        return value[key]
-      end),
+      observable = subject
+        :filter(function(_, k)
+          return k == nil or k == key
+        end)
+        :map(function(value)
+          return value[key]
+        end),
     },
   }

[mobily]

it's certainly a bug (created a new issue, #32)