Repository Analysis

TanStack/virtual

🤖 Headless UI for Virtualizing Large Element Lists in JS/TS, React, Solid, Vue and Svelte

2.9 Likely human-written View on GitHub

Analysis Overview

This report presents the forensic synthetic code analysis of TanStack/virtual, a TypeScript project with 7,004 GitHub stars. SynthScan v2.0 examined 52,694 lines of code across 585 source files, recording 73 pattern matches distributed across 6 syntactic categories. The overall adjusted score of 2.9 places this repository in the Likely human-written band.

The scanner applied 160+ deterministic lexical heuristics, multi-line block detectors, abstract syntax tree depth profilers, and a cross-file Jaccard similarity matrix to construct a statistically normalised synthetic code estimate. All matches are individually weighted by severity coefficient and contextual multiplier before summation, and the resulting headline score is temporally discounted to account for the repository's development history relative to the commercial emergence of large language model coding tooling (November 2022 onward).

2.9
Adjusted Score
2.9
Raw Score
100%
Time Factor
2026-07-14
Last Push
7.0K
Stars
TypeScript
Language
52.7K
Lines of Code
585
Files
73
Pattern Hits
2026-07-14
Scan Date
0.00
HC Hit Rate

What These Metrics Mean

Adjusted Score
Primary synthetic code indicator. Raw score normalised per 1,000 lines of code and multiplied by the temporal discount factor. This is the definitive comparative metric — use it to rank repositories by AI authorship density.
Raw Score
The unmodified sum of all severity-weighted, context-multiplied pattern match scores before temporal discounting. Reflects the absolute signal strength independent of when the repository was last active.
Time Factor
The temporal discount multiplier (0–100%) applied to the raw score. Repositories last updated before ChatGPT's launch (Nov 2022) receive a 5% factor. Full signal is only assigned to repositories active in the post-adoption era (Jan 2024+).
Pattern Hits
Total count of individual pattern matches across all files and categories. A high hit count with a low score may indicate a very large codebase with isolated AI snippets; a low count with a high score indicates dense, concentrated AI signatures.
HC Hit Rate
High+Critical pattern hits per file, averaged across the repository. This orthogonal signal catches repositories where a few files are densely packed with high-severity AI tells — a strong indicator even when the normalised score appears moderate due to codebase size.
Lines of Code / Files
Total lines and files analysed. The scanner examines 94 file extensions. These denominators are used to normalise the score, enabling fair comparison between repositories of vastly different sizes.

Score History

Longitudinal tracking requires multiple scan runs. Once this repository is re-scanned after new commits land, this chart will visualise how the synthetic code signal evolves over time — enabling you to detect whether AI authorship is growing, stabilising, or being actively corrected by human engineers.

No multi-scan history yet — run the scanner again to build trend data.

Severity Breakdown

Classifies detected patterns by their diagnostic confidence and structural impact. CRITICAL patterns (coefficient 10) represent definitive synthetic signatures — hallucinated imports, explicit LLM attribution metadata — virtually never produced by human authors. HIGH (5) indicates strong structural tells such as cross-file repetition or cross-linguistic idioms. MEDIUM (2) covers recognisable conversational padding and AI-specific vocabulary. LOW (1) captures subtle indicators like tautological comments and generic boilerplate that require density to carry independent signal.

CRITICAL 0HIGH 0MEDIUM 31LOW 42

Directory Score Breakdown

This horizontal bar chart decomposes the repository's raw synthetic code score by top-level directory, allowing you to pinpoint precisely which modules or components carry the highest AI authorship density. Directories with disproportionately high scores relative to their size warrant targeted manual review: concentrated AI signatures often trace back to mass-generated configuration layers, auto-ported test suites, LLM-scaffolded boilerplate classes, or entire subsystems authored under heavy copilot assistance. Use this view to prioritise your human code-review effort.

Pattern Findings

The scanner identified 73 distinct pattern matches across 6 syntactic categories. Each entry below represents a discrete location in the source code where the engine recorded a statistically significant AI authorship indicator. Expand any category row to inspect the individual file paths, line numbers, code snippets, and the lexical context (CODE, COMMENT, or STRING) in which each match was detected.

Reading the findings table: The Severity column indicates the diagnostic confidence level (CRITICAL / HIGH / MEDIUM / LOW). The Context column identifies whether the match occurred inside executable code, an inline comment, or a string literal — comment-context matches receive a ×1.5 weight because LLMs systematically over-annotate. The ⚡ bolt icon marks clustered matches: three or more patterns within a 10-line window, each receiving an additional ×1.5 density multiplier as dense clusters constitute far stronger evidence of synthetic authorship than isolated hits.

Decorative Section Separators22 hits · 66 pts
SeverityFileLineSnippetContext
MEDIUMpackages/virtual-core/tests/index.test.ts514// ─── resizeItem / measurement cache invalidation ─────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts773// ─── elementsCache leak: disconnected node cleanup ───────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts943// ─── setOptions behavioral contract ──────────────────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts1085// ─── pending min pointer for measure storms ──────────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts1158// ─── defaultRangeExtractor ───────────────────────────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts1235// ─── Lazy fast path (lanes === 1) edge cases ─────────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts1426// ─── iOS momentum-safe scroll adjustments ───────────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts1591// ─── Phase 1: touch event distinction ────────────────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts1941// ─── Phase 2a: subpixel scrollTop reconciliation ─────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts2013// ─── Phase 2b: scrollTopMax elastic-overscroll clamp ─────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts2389// ─── scroll direction vs. self-write read-backs ─────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts2586// ─── end anchoring / chat-style reverse virtualization ──────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts2953// ─── elementScroll / windowScroll public exports ─────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts3021// ─── observeElementOffset / observeWindowOffset ──────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/index.test.ts3119// ─── Public-exports lockdown ─────────────────────────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/bench.bench.ts25// ─── Exp 1: Cold-mount cost — getMeasurements with no measured items ─────────COMMENT
MEDIUMpackages/virtual-core/tests/bench.bench.ts61// ─── Layer 1: Map clone bug — resizeItem under measure storm ─────────────────COMMENT
MEDIUMpackages/virtual-core/tests/bench.bench.ts175// ─── Layer 2: setOptions per render ──────────────────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/bench.bench.ts203// ─── Scroll loop: per-scroll-frame cost (calculateRange + memo machinery) ─────COMMENT
MEDIUMpackages/virtual-core/tests/bench.bench.ts230// ─── Layer 6: defaultRangeExtractor ──────────────────────────────────────────COMMENT
MEDIUMpackages/virtual-core/tests/bench.bench.ts247// ─── Multi-lane: cold-mount lane assignment (getFurthestMeasurement) ──────────COMMENT
MEDIUMpackages/virtual-core/src/index.ts1207 // ─── Fast path: single-lane lazy materialization ────────────────────COMMENT
Modern AI Meta-Vocabulary9 hits · 27 pts
SeverityFileLineSnippetContext
MEDIUMexamples/angular/infinite-scroll/README.md9## Code scaffoldingCOMMENT
MEDIUMexamples/angular/dynamic/README.md9## Code scaffoldingCOMMENT
MEDIUMexamples/angular/variable/README.md9## Code scaffoldingCOMMENT
MEDIUMexamples/angular/sticky/README.md9## Code scaffoldingCOMMENT
MEDIUMexamples/angular/fixed/README.md9## Code scaffoldingCOMMENT
MEDIUMexamples/angular/table/README.md9## Code scaffoldingCOMMENT
MEDIUMexamples/angular/window/README.md9## Code scaffoldingCOMMENT
MEDIUMexamples/angular/padding/README.md9## Code scaffoldingCOMMENT
MEDIUMexamples/angular/smooth-scroll/README.md9## Code scaffoldingCOMMENT
Verbosity Indicators8 hits · 18 pts
SeverityFileLineSnippetContext
LOW…s/angular-virtual/e2e/app/test/measure-element.spec.ts13 // Step 1: Expand A → should grow to ~160pxCOMMENT
LOW…s/angular-virtual/e2e/app/test/measure-element.spec.ts17 // Step 2: Collapse A → back to ~36pxCOMMENT
LOW…s/angular-virtual/e2e/app/test/measure-element.spec.ts21 // Step 3: Delete ACOMMENT
LOW…s/angular-virtual/e2e/app/test/measure-element.spec.ts25 // Step 4: Expand B → should grow to ~160pxCOMMENT
LOW…ges/react-virtual/e2e/app/test/measure-element.spec.ts13 // Step 1: Expand A → should grow to ~160pxCOMMENT
LOW…ges/react-virtual/e2e/app/test/measure-element.spec.ts17 // Step 2: Collapse A → back to ~36pxCOMMENT
LOW…ges/react-virtual/e2e/app/test/measure-element.spec.ts21 // Step 3: Delete ACOMMENT
LOW…ges/react-virtual/e2e/app/test/measure-element.spec.ts25 // Step 4: Expand B → should grow to ~160pxCOMMENT
Structural Annotation Overuse8 hits · 18 pts
SeverityFileLineSnippetContext
LOW…s/angular-virtual/e2e/app/test/measure-element.spec.ts13 // Step 1: Expand A → should grow to ~160pxCOMMENT
LOW…s/angular-virtual/e2e/app/test/measure-element.spec.ts17 // Step 2: Collapse A → back to ~36pxCOMMENT
LOW…s/angular-virtual/e2e/app/test/measure-element.spec.ts21 // Step 3: Delete ACOMMENT
LOW…s/angular-virtual/e2e/app/test/measure-element.spec.ts25 // Step 4: Expand B → should grow to ~160pxCOMMENT
LOW…ges/react-virtual/e2e/app/test/measure-element.spec.ts13 // Step 1: Expand A → should grow to ~160pxCOMMENT
LOW…ges/react-virtual/e2e/app/test/measure-element.spec.ts17 // Step 2: Collapse A → back to ~36pxCOMMENT
LOW…ges/react-virtual/e2e/app/test/measure-element.spec.ts21 // Step 3: Delete ACOMMENT
LOW…ges/react-virtual/e2e/app/test/measure-element.spec.ts25 // Step 4: Expand B → should grow to ~160pxCOMMENT
Over-Commented Block14 hits · 14 pts
SeverityFileLineSnippetContext
LOWexamples/svelte/infinite-scroll/src/vite-env.d.ts1/// <reference types="svelte" />COMMENT
LOWexamples/svelte/dynamic/src/vite-env.d.ts1/// <reference types="svelte" />COMMENT
LOWexamples/svelte/sticky/src/vite-env.d.ts1/// <reference types="svelte" />COMMENT
LOWexamples/svelte/fixed/src/vite-env.d.ts1/// <reference types="svelte" />COMMENT
LOWexamples/svelte/table/src/vite-env.d.ts1/// <reference types="svelte" />COMMENT
LOWexamples/svelte/smooth-scroll/src/vite-env.d.ts1/// <reference types="svelte" />COMMENT
LOWbenchmarks/src/lib/harness.ts241 ) {COMMENT
LOWpackages/virtual-core/tests/index.test.ts2381 v['getMeasurements']()COMMENT
LOWpackages/virtual-core/tests/index.test.ts2541 // width animation re-wraps rows for several frames while the user sitsCOMMENT
LOWpackages/virtual-core/tests/lane-equivalence.test.ts1// Differential ("oracle") test for the multi-lane lane-assignment optimization.COMMENT
LOWpackages/virtual-core/src/index.ts421 scrollOffset: number | null = nullCOMMENT
LOWpackages/virtual-core/src/index.ts621 }COMMENT
LOWpackages/virtual-core/src/index.ts801 // A scroll event that reports movement but lands on the offset weCOMMENT
LOWpackages/virtual-core/src/index.ts1201COMMENT
Hyper-Verbose Identifiers12 hits · 12 pts
SeverityFileLineSnippetContext
LOWexamples/react/dynamic/src/main.tsx292function RowVirtualizerExperimental() {CODE
LOWexamples/react/variable/src/main.tsx107function ColumnVirtualizerVariable({ columns }: { columns: Array<number> }) {CODE
LOWexamples/react/variable/src/main.tsx236function MasonryVerticalVirtualizerVariable({ rows }: { rows: Array<number> }) {CODE
LOWexamples/react/variable/src/main.tsx287function MasonryHorizontalVirtualizerVariable({CODE
LOWscripts/verify-links.ts51function fileExistsForMarkdownLink(CODE
LOWpackages/angular-virtual/src/index.ts51function injectScheduleDomFlushViaAppRefTick() {CODE
LOWpackages/virtual-core/tests/index.test.ts1613function makeIOSVirtualizerWithRealEl(CODE
LOWpackages/virtual-core/tests/index.test.ts1816function makeIOSVirtualizerWithSwappableEl(CODE
LOWpackages/virtual-core/tests/index.test.ts2401function createAdjustmentVirtualizer({CODE
LOWpackages/virtual-core/src/index.ts1935function findNearestBinarySearchFlat(CODE
LOWpackages/virtual-core/src/lazy-measurements.ts10export function createLazyMeasurementsView(CODE
LOWpackages/react-virtual/e2e/app/test/chat.spec.ts64async function waitForFirstVisibleAtOffset(page: Page, scrollTop: number) {CODE