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Complexity Indicator
A VS Code extension that analyses the complexity of your active file in real time and displays a rich metrics dashboard in the sidebar — built with Flutter/Dart developers in mind, but works with any language. Features
Metrics ExplainedComplexity Score
|
| Weight | Signal |
|---|---|
| 35% | Cyclomatic Complexity |
| 25% | Max Nesting Depth |
| 20% | Lines of Code |
| 12% | Average Parameters |
| 8% | Function Count |
Grades:
| Score | Grade | Label |
|---|---|---|
| 0 – 20 | A | Low |
| 21 – 40 | B | Medium |
| 41 – 60 | C | High |
| 61 – 80 | D | Very High |
| 81 – 100 | F | Critical |
Maintainability Index 0 – 100
Based on the Microsoft Maintainability Index formula, normalised to a 0 – 100 scale. Higher is better.
MI = 171 − 0.23 × CC − 16.2 × ln(LOC) + 50 × √(2.46 × commentRatio)
Normalised = MAX(0, MI × 100 / 171)
| Range | Rating |
|---|---|
| ≥ 85 | Excellent |
| ≥ 70 | Good |
| ≥ 50 | Fair |
| < 50 | Poor — consider refactoring |
Lines of Code (LOC)
Non-blank, non-comment lines — only the lines that actually execute. Block comments (/* */) and line comments (//) are excluded.
Rule of thumb: keep files under 300 LOC for readability.
Function Count
Total number of function or method declarations detected in the file.
Files with > 15 functions often benefit from being split into smaller modules.
Cyclomatic Complexity
Counts the number of independent execution paths through the code (McCabe, 1976). Starts at 1 and increments for every decision point:
if · else if · for · while · do · catch · case · && · || · ?. · ?? · ternary ?
| Value | Meaning |
|---|---|
| ≤ 10 | Simple, easy to test |
| 11 – 20 | Moderate complexity |
| > 20 | High risk — hard to test and maintain |
Max Nesting Depth
The deepest level of nested control flow structures (if, for, while, try, etc.).
| Depth | Status |
|---|---|
| ≤ 2 | Good (shown in green) |
| 3 – 4 | Warning (shown in orange) |
| ≥ 5 | Danger (shown in red) |
Google's engineering guidelines recommend keeping nesting at ≤ 3 levels. Use early returns and guard clauses to flatten nesting.
Average Parameters
The average number of parameters across all functions in the file.
Functions with > 4 parameters are harder to call, read, and test. Consider grouping related parameters into a class or object.
Comment Ratio
The percentage of total lines that are comments.
A healthy ratio is 15 – 30%. Too low may mean under-documented code; too high may indicate outdated or noisy comments.
Import Count
The total number of import statements in the file.
A high import count can indicate tight coupling or a file doing too much. Consider extracting responsibilities into dedicated helpers.