Free Developer Tool
Paste any JavaScript code and instantly visualize a dependency graph showing all module imports, detect circular dependencies, and analyze code structure. Works with React, Angular, Node.js, and vanilla JS — no installation required.
// Paste JavaScript code to analyze
// Example JavaScript dependency graph output
// Core concept
A JavaScript dependency graph is a directed graph that maps the relationships between modules in your codebase. Each node represents a file or module, and each edge represents an import or require relationship. This graph is fundamental to how modern build tools work.
When webpack, Vite, Rollup, or esbuild bundles your application, they construct an internal dependency graph starting from an entry point and following every import and require statement. This graph determines what code gets bundled, what gets tree-shaken (removed as unused), and how modules are organized in the final bundle.
A JavaScript dependency graph reveals several critical insights: circular dependencies that cause bugs, unused imports that bloat your bundle, highly connected modules that are hard to refactor, and dependency chains that affect performance.
// Use cases
Understanding your codebase's dependency structure is essential for debugging, optimizing, and refactoring. Here are the key reasons developers analyze dependency graphs:
Circular imports cause undefined values and silent bugs. Visualizing dependencies immediately reveals these problematic cycles so you can refactor before they crash production.
Dependency graphs show which npm packages are imported most frequently. Identify and remove unused dependencies to shrink your bundle and improve load times.
Before splitting a module or extracting utilities, visualize how many other files depend on it. Understand the blast radius of changes before you make them.
Show new team members a dependency graph of key modules to help them understand the codebase structure without reading dozens of import statements.
Build tool errors from unresolved imports become easier to trace when you can see the complete dependency map of a file.
See exactly how many modules depend on a specific npm package before upgrading, replacing, or removing it from your project.
// How to use
This tool analyzes code entirely in your browser. No installation, no configuration, no terminal commands required.
import and require() statements in your code, classifies each dependency by type (local files, npm packages, Node built-ins), and checks for circular reference risks.
// Common problem
The most common JavaScript dependency problem is circular dependencies — when two or more modules import each other. Understanding why this happens and how to detect it is critical for maintaining reliable code.
Why circular dependencies happen:
Consider a file structure like this: a component imports a utility file, and that utility file imports a helper from the component. This creates a cycle:
When JavaScript tries to resolve this cycle, it returns an incomplete or undefined module object to one of the importers. Your code tries to use a function that doesn't exist yet, resulting in silent undefined errors that are notoriously hard to debug.
How to find and fix them:
Paste the suspected circular files into this tool. If the same module appears in multiple import paths, it's flagged as a circular risk. To fix: extract shared code into a separate utility file that neither module imports — breaking the cycle. This dependency graph tool identifies the problem; refactoring breaks the cycle.
// Classification
This tool classifies all imported modules into three categories, each with different implications for your codebase:
Files in your own project imported via relative paths like ./components/Header or ../utils/api. These are the core of your codebase structure and dependencies you fully control.
Third-party libraries from npm like react, axios, lodash. These appear in your dependency graph but live in node_modules. Heavy use of specific packages can impact bundle size.
Modules like fs, path, http, crypto. These are free in Node.js but cannot be bundled for browsers without polyfills. Important to track when building isomorphic/universal code.
When the same local module is imported from multiple paths, it's flagged as a potential circular dependency. These need refactoring to prevent undefined errors.
// Community questions
Common questions from developers trying to understand and analyze their codebase dependencies:
How do I find circular dependencies in my JavaScript code?
Paste the file you suspect into this tool. The tool scans all import and require statements and flags any modules that appear in multiple import paths — a pattern indicating circular dependency risk. This is much faster than manually reading through dozens of import statements.
What's the difference between a dependency graph and a module tree?
In JavaScript, these terms are often used interchangeably. A dependency graph shows relationships between modules (which imports which). A module tree is the hierarchical structure of those relationships starting from an entry point. This tool visualizes the dependency graph as a tree starting from your code.
Does webpack create a dependency graph internally?
Yes. Every bundler (webpack, Vite, Rollup, esbuild) builds an internal dependency graph to determine what to bundle, what to tree-shake, and how to split chunks. Understanding your code's dependency structure helps you predict bundler behavior and optimize the output.
How does analyzing dependencies help reduce bundle size?
A dependency graph shows all npm packages your code imports. If you see a package imported in many places, it's bundled. This visualization helps identify: unused imports you can delete, packages used by only one module that could be moved to dev dependencies, and code duplication across modules that could be extracted.
Can I use this tool to understand React component dependencies?
Yes. React components are standard JavaScript files with ES6 imports. Paste any component file and the tool maps all dependencies: other React components, hooks, utility functions, npm packages, and CSS imports (if present). This helps understand component coupling and identify tightly-bound components that should be split.
What's the performance impact of having many dependencies?
More dependencies = larger bundle size (more code to download), longer parse/eval time (more JavaScript to process), and more potential for conflicts. A dependency graph shows where your code is heavy. Combined with webpack's bundle analyzer, you can identify and optimize the biggest contributors.
// FAQ