# bogdan-lyashenko/under-the-hood-reactjs

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6,835 stars · 614 forks · JavaScript · mit

## Links

- GitHub: https://github.com/Bogdan-Lyashenko/Under-the-hood-ReactJS
- Homepage: https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/
- awesome-repositories: https://awesome-repositories.com/repository/bogdan-lyashenko-under-the-hood-reactjs.md

## Topics

`debugging` `fiber` `flow` `hood` `javascript` `reactjs` `reconciliation` `scheme` `stack` `virtualdom` `visualization` `webdevelopment`

## Description

This project is a technical breakdown and implementation of a user interface framework's internal architecture, focusing specifically on the mechanics of the virtual DOM, reconciliation, and component lifecycles. It serves as a resource for understanding how a core logic layer manages the transition from high-level component descriptions to physical browser elements.

The project distinguishes itself by providing detailed visualizations, including flowcharts and block schemes, to map the reconciliation process and code execution paths. It explores how a platform-agnostic core can be adapted for different environments, such as mobile, browser, and server, using platform-specific injectors.

The implementation covers several core framework capabilities, including recursive tree construction, transaction-based update batching to prevent redundant render cycles, and prop-diffing to minimize DOM mutations. It also includes systems for prop validation, state update queuing, and the management of component lifecycle hooks.

## Tags

### Education & Learning Resources

- [Framework Internals Education](https://awesome-repositories.com/f/education-learning-resources/framework-internals-education.md) — Provides a technical breakdown of how a UI framework manages the virtual DOM, reconciliation, and lifecycles.

### Web Development

- [Virtual DOM Reconciliation](https://awesome-repositories.com/f/web-development/virtual-dom-reconciliation.md) — Implements the core reconciliation strategy to efficiently update the browser DOM by minimizing direct manipulations.
- [Asynchronous Update Queues](https://awesome-repositories.com/f/web-development/frontend-development-tools/state-data-management/data-synchronization-primitives/asynchronous-update-queues.md) — Implements mechanisms to buffer state changes in queues to optimize rendering and batch operations. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-8.html))
- [JSX Compilers](https://awesome-repositories.com/f/web-development/jsx-compilers.md) — Implements the transformation of high-level JSX descriptions into plain JavaScript objects for UI construction.
- [JSX Transformers](https://awesome-repositories.com/f/web-development/jsx-transformers.md) — Implements a system to convert high-level JSX descriptions into plain JavaScript objects for UI representation. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-0.html))
- [Virtual DOM Diffing](https://awesome-repositories.com/f/web-development/virtual-dom-diffing.md) — Implements algorithms for calculating minimal updates between virtual tree snapshots and the real DOM.
- [Lifecycle Hooks](https://awesome-repositories.com/f/web-development/application-lifecycle-hooks/lifecycle-hooks.md) — Analyzes the sequence of hooks during the initial mount and render trigger process. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-3.html))
- [Frontend Performance Optimization](https://awesome-repositories.com/f/web-development/frontend-performance-optimization.md) — Implements batching and diffing algorithms to prevent redundant renders and improve interface update efficiency.

### Graphics & Multimedia

- [Surgical DOM Update Engines](https://awesome-repositories.com/f/graphics-multimedia/graphics-engines-rendering/rendering/systems/dom-web-rendering-strategies/surgical-dom-update-engines.md) — Provides a surgical update engine that modifies only affected DOM nodes based on virtual representation changes. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-14.html))
- [DOM Reconciliation](https://awesome-repositories.com/f/graphics-multimedia/graphics-engines-rendering/rendering/systems/dom-web-rendering-strategies/surgical-dom-update-engines/dom-reconciliation.md) — Performs granular DOM updates by comparing property values and applying only necessary changes. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-5.html))
- [Cross-Platform Rendering Engines](https://awesome-repositories.com/f/graphics-multimedia/graphics-engines-rendering/rendering/engines/multi-mode-rendering-strategies/cross-platform-rendering-engines.md) — Develops a core engine that interprets markup to construct visual interfaces across mobile, browser, and server platforms.

### Software Engineering & Architecture

- [Component Instantiation](https://awesome-repositories.com/f/software-engineering-architecture/component-lifecycle-management/application-component-lifecycles/component-instantiation.md) — Implements the process of creating functional instances of components within a runtime environment. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-6.html))
- [Virtual-to-DOM Mappings](https://awesome-repositories.com/f/software-engineering-architecture/dynamic-schema-mapping/component-mappings/virtual-to-dom-mappings.md) — Links virtual framework component trees to their corresponding physical DOM elements for rendering. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-0.html))
- [Platform-Specific API Implementations](https://awesome-repositories.com/f/software-engineering-architecture/polymorphism-patterns/platform-specific-api-implementations.md) — Uses platform-specific injectors to map unified core logic to concrete environment implementations. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/languages/korean/book/Intro.html))
- [Post-Update Callbacks](https://awesome-repositories.com/f/software-engineering-architecture/reactive-update-scheduling/post-update-callbacks.md) — Executes post-update callbacks once the DOM has finished updating to synchronize state. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-14.html))
- [Incremental Reconciliation](https://awesome-repositories.com/f/software-engineering-architecture/trees/incremental-reconciliation.md) — Implements and documents mechanisms for updating only modified branches of a tree structure during the reconciliation process. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/))
- [Recursive Component Instantiation](https://awesome-repositories.com/f/software-engineering-architecture/trees/syntax-tree-construction/dom-tree-construction/recursive-component-instantiation.md) — Constructs a complete interface hierarchy by instantiating components from the top level down to children.
- [Component Render Sequencing](https://awesome-repositories.com/f/software-engineering-architecture/component-render-sequencing.md) — Ensures parent components are updated before children during a reconciliation batch to maintain UI consistency.
- [Framework Logic Visualizations](https://awesome-repositories.com/f/software-engineering-architecture/go-api-architecture-design/architecture-visualizations/framework-logic-visualizations.md) — Provides detailed visual block schemes and flowcharts to illustrate internal framework logic and the reconciliation process. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/fiber/book/Intro.html))
- [Logic Visualizers](https://awesome-repositories.com/f/software-engineering-architecture/logic-visualizers.md) — Maps the internal execution flow and state transitions of the reconciliation process using visual diagrams. ([source](https://cdn.jsdelivr.net/gh/bogdan-lyashenko/under-the-hood-reactjs@master/README.md))
- [Update Cycle Controllers](https://awesome-repositories.com/f/software-engineering-architecture/reactive-update-scheduling/update-cycle-controllers.md) — Uses batch counters to decide if a component update should proceed, preventing redundant renders. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-10.html))
- [Execution Flow Visualizations](https://awesome-repositories.com/f/software-engineering-architecture/state-transition-models/visual-state-transitions/execution-flow-visualizations.md) — Maps code execution and state transitions within the engine using visual flowcharts. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/))

### User Interface & Experience

- [Component Lifecycle Hooks](https://awesome-repositories.com/f/user-interface-experience/component-lifecycle-hooks.md) — Provides mechanisms to execute custom logic during component rendering, updating, or removal phases.
- [Component Lifecycle Triggers](https://awesome-repositories.com/f/user-interface-experience/component-lifecycle-triggers.md) — Manages the execution of logic and callbacks immediately after components mount to the DOM. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-7.html))
- [Custom UI Component Frameworks](https://awesome-repositories.com/f/user-interface-experience/custom-ui-component-frameworks.md) — Implements a custom component-based framework with state management, prop validation, and recursive tree mounting.
- [Physical DOM Instantiations](https://awesome-repositories.com/f/user-interface-experience/physical-dom-instantiations.md) — Translates virtual representations into real browser elements by instantiating them via the native document API. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-4.html))
- [Platform-Agnostic Renderers](https://awesome-repositories.com/f/user-interface-experience/platform-agnostic-renderers.md) — Abstracts the virtual node creation from the mounting process to support multiple target environments.
- [Recursive Component Mounting](https://awesome-repositories.com/f/user-interface-experience/recursive-component-mounting.md) — Implements the recursive process of mounting an interface tree from the top-level wrapper down to all child components. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-3.html))
- [Renderer Reconciler Abstractions](https://awesome-repositories.com/f/user-interface-experience/renderer-reconciler-abstractions.md) — Separates the core UI tree reconciliation logic from platform-specific rendering targets. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-14.html))
- [Update Batching](https://awesome-repositories.com/f/user-interface-experience/update-batching.md) — Groups multiple state changes into single render cycles to prevent redundant updates.
- [Virtual DOM Implementations](https://awesome-repositories.com/f/user-interface-experience/virtual-dom-implementations.md) — Builds a system that maintains memory-based interface representations to optimize rendering performance via diffing.
- [Virtual DOM Rendering Engines](https://awesome-repositories.com/f/user-interface-experience/virtual-dom-rendering-engines.md) — Utilizes a virtual DOM rendering engine to optimize view updates via minimal change calculation. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-12.html))
- [Component Update Optimizations](https://awesome-repositories.com/f/user-interface-experience/component-update-optimizations.md) — Tracks changes to properties and state to determine when a component requires a re-render. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-11.html))
- [Component Prop Validation](https://awesome-repositories.com/f/user-interface-experience/component-utilities/ui-frameworks/component-apis/component-prop-validation.md) — Ships mechanisms for verifying the types and requirements of data passed into UI components. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-4.html))
- [Cross-Platform Implementations](https://awesome-repositories.com/f/user-interface-experience/cross-platform-ui-design-patterns/cross-platform-implementations.md) — Provides analysis of how core UI logic is implemented consistently across mobile, browser, and server environments. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/languages/chinese/book/Intro.html))
- [Component Lifecycle Management](https://awesome-repositories.com/f/user-interface-experience/presentation-frameworks/lifecycle-state-management/component-lifecycle-management.md) — Uses schemas to visualize the internal logic of component mounting and updating processes. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/languages/chinese/book/Intro.html))

### Development Tools & Productivity

- [Component Instance Initializers](https://awesome-repositories.com/f/development-tools-productivity/instance-initialization/component-instance-initializers.md) — Extends component instances with properties and context while assigning platform-specific updaters to handle state. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Part-3.html))

### DevOps & Infrastructure

- [Dependency Mapping Utilities](https://awesome-repositories.com/f/devops-infrastructure/dependency-management/environment-scoping-controls/linked-dependency-management/module-based-dependency-managers/dependency-mapping-utilities.md) — Maps the relationships between core architecture modules and their utilization across different platform environments. ([source](https://bogdan-lyashenko.github.io/Under-the-hood-ReactJS/stack/book/Intro.html))