nil

Package Overview

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The nil package provides a minimal, performance-optimized widget that renders nothing when included in the widget tree. It's designed for scenarios where you need a placeholder or conditional widget that doesn't contribute to layout or rendering overhead. Unlike SizedBox.shrink() or Container(), nil has zero impact on the widget tree’s performance and is ideal for dynamic UI logic where visibility conditions are handled externally. It's lightweight and safe to use in complex or frequently updated UIs.

Use cases

Conditional rendering with no visual output
Replacing empty containers in dynamic layouts
Optimizing performance in large widget trees
Simplifying null checks in widget composition
Avoiding unnecessary layout calculations

Key features

Zero rendering cost
No layout impact
Minimal memory footprint
Simple API
Safe for frequent updates

Suitable for

Developers optimizing UI performance
Builders of dynamic or conditional UIs
Teams prioritizing minimal overhead
Apps with complex or nested widget trees
Those seeking a clean alternative to empty widgets

Considerations

Not suitable for visible content
Does not support child widgets
Only useful when intentionally rendering nothing
Not needed if using built-in null-safe constructs
Best used in conjunction with conditional logic

Original README

Original README snapshot from the linked source repository. Visit the repository for the latest content.

A simple widget to add in the widget tree when you want to show nothing, with minimal impact on performance.

Why?

Sometimes, according to a condition, we want to display nothing. Usually when we can't return null, we would return something like const SizedBox() for example.

This is good, but it has some performance impacts since SizedBox creates a RenderObject. The RenderObject lives in the render tree and some computations are performed on it, even if it paints nothing on the screen.

We can do better, we can have a widget which does not create a RenderObject, while being still valid. The Nil widget is the minimal implementation for this use case. It only creates an Element and does nothing while it's building. Because the optimal way to use it, is to call const Nil(), it also comes with a nil constant that you can use everywhere (which is a const Nil()).

Usage

import 'package:nil/nil.dart';

return Builder(
  builder: (_) {
    if (condition) {
      return const MyWidget();
    } else {
      return nil;
    }
  },
);

Warning

This widget is not intended to be used in widgets accepting multiple children (e.g. Rows, Columns, etc.). The best option is to not add a widget in the list if you don't want it to be displayed. Moreover using a Nil widget in such a case, can have unexpected results.

Sponsoring

I'm working on my packages on my free-time, but I don't have as much time as I would. If this package or any other package I created is helping you, please consider to sponsor me so that I can take time to read the issues, fix bugs, merge pull requests and add features to these packages.

Contributions

Feel free to contribute to this project.

If you find a bug or want a feature, but don't know how to fix/implement it, please fill an issue.
If you fixed a bug or implemented a feature, please send a pull request.