What is cyclomatic complexity?

Cyclomatic complexity measures the number of linearly independent paths through a function's source code by counting branches such as if statements, loops, and case clauses. Higher values indicate more test cases are required for full coverage.

Which programming languages are supported?

The analyzer supports JavaScript, TypeScript, Python, Java, and Go. You can manually select the language or use auto-detect to identify the syntax automatically.

How does cognitive complexity differ from cyclomatic complexity?

While cyclomatic complexity counts branches mathematically, cognitive complexity assesses how difficult code is for humans to understand, penalizing nested structures and logical jumps more heavily than simple sequential branches.

What does the duplicate window setting control?

The duplicate window defines the minimum number of consecutive tokens that must match to flag code as potentially duplicated. Lower values catch smaller similarities, while higher values identify only substantial copy-pasted blocks.

Can I analyze multiple files or entire projects?

Currently, the tool analyzes one code snippet at a time via paste input. For project-wide analysis, run the tool separately on individual files or aggregate critical modules into a single paste.

Code Complexity Analyzer | Online Free Tool

Examples

1. Simplify Nested JavaScript Pricing Logic

Senior Frontend Developer

Background

A legacy checkout module contains a pricing function with multiple nested conditionals for discounts and VIP status, making it difficult to unit test and maintain safely.

Problem

The function has hidden complexity and deep nesting that increases bug risk during feature updates, but the exact metrics are unknown.

How to use

Paste the score function code into the Source Code field, select JavaScript as the language, and set the nesting threshold to 2 to catch deep conditional blocks.

{
  "language": "javascript",
  "longFunctionThreshold": 8,
  "nestingThreshold": 2,
  "duplicateWindow": 4
}

Outcome

Analysis reveals cyclomatic complexity of 5 and flags deep nesting, prompting the team to extract discount logic into separate functions for improved testability and reduced cognitive load.

2. Deduplicate Python Data Normalization Helpers

Backend Engineer

Background

A data processing pipeline contains two nearly identical helper functions for normalizing user and admin records, created through copy-paste development over multiple sprints.

Problem

Duplicate logic increases maintenance burden and risks inconsistent updates when business rules change, but the similarity was not obvious during manual review.

{
  "language": "python",
  "longFunctionThreshold": 20,
  "nestingThreshold": 3,
  "duplicateWindow": 3
}

Code Complexity Analyzer | Online Free Tool | Elysia Tools

Code Complexity Analyzer

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1. Simplify Nested JavaScript Pricing Logic

2. Deduplicate Python Data Normalization Helpers

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