JavaScript library to zip and unzip files supporting multi-core compression, web streams, zip64, split files, data encryption, and deflate64 decompression.
This report presents the forensic synthetic code analysis of gildas-lormeau/zip.js, a JavaScript project with 3,871 GitHub stars. SynthScan v2.0 examined 41,550 lines of code across 322 source files, recording 206 pattern matches distributed across 5 syntactic categories. The overall adjusted score of 5.1 places this repository in the Low AI signal 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).
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.
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.
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.
The scanner identified 206 distinct pattern matches across 5 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.
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | index.d.ts | 2342 | * const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidu | COMMENT |
| LOW | index.d.ts | 2342 | * const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidu | COMMENT |
| LOW | tests/all/test-split-data.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-split-data.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-overlapping-entries.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-overlapping-entries.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-export-options.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-export-options.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-crypto-tampered.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-crypto-tampered.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-unzip-store.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-unzip-store.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-comments.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-comments.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-arraybuffer.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-arraybuffer.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-remove-entry.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-remove-entry.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-last-access-date.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-last-access-date.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-malformed-zip.js | 3 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-malformed-zip.js | 3 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-remove.js | 3 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-remove.js | 3 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64-crypto.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64-crypto.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-worker-error.js | 6 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-worker-error.js | 6 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-golden-output.js | 24 | await zipWriter.add("text.txt", new zip.TextReader("Lorem ipsum dolor sit amet"), { comment: "entry comment" }); | CODE |
| LOW | tests/all/test-golden-output.js | 24 | await zipWriter.add("text.txt", new zip.TextReader("Lorem ipsum dolor sit amet"), { comment: "entry comment" }); | CODE |
| LOW | tests/all/test-fs-http-import.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-http-import.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64-local-compressed-size.js | 52 | const text = "Lorem ipsum dolor sit amet ".repeat(80); | CODE |
| LOW | tests/all/test-zip64-local-compressed-size.js | 52 | const text = "Lorem ipsum dolor sit amet ".repeat(80); | CODE |
| LOW | tests/all/test-wrapped.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-wrapped.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-writer-edge-cases.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-writer-edge-cases.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-writer-js-codec-fallback.js | 15 | const CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. ".repeat(256); | CODE |
| LOW | tests/all/test-writer-js-codec-fallback.js | 15 | const CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. ".repeat(256); | CODE |
| LOW | tests/all/test-split-zip.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-split-zip.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64-auto.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64-auto.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64-no-compression.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64-no-compression.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-custom-io.js | 3 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-custom-io.js | 3 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64-buffered-no-data-descriptor.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip64-buffered-no-data-descriptor.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-store.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-store.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-readable-zip-stream.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-readable-zip-stream.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip-streams.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-zip-streams.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-metadata.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| LOW | tests/all/test-fs-metadata.js | 5 | const TEXT_CONTENT = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt | CODE |
| 116 more matches not shown… | ||||
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | tests/all/test-malformed-zip.js | 81 | function addCentralDirectoryExtraField(array, extraField, patchDirectoryRecord) { | CODE |
| LOW | tests/all/test-abort-buffered-flush-offset.js | 114 | function firstCentralDirectoryOffset(bytes) { | CODE |
| LOW | tests/all/test-abort-buffered-flush-offset.js | 124 | function endOfCentralDirectoryOffset(bytes) { | CODE |
| LOW | tests/all/test-writer-edge-cases.js | 22 | async function testDuplicateDirectoryName() { | CODE |
| LOW | tests/all/test-io-edge-cases.js | 19 | async function testSplitDataWriterExactFill() { | CODE |
| LOW | tests/all/test-io-edge-cases.js | 48 | async function testHttpReaderIgnoredRangeRequest() { | CODE |
| LOW | tests/all/test-use-unicode-file-names.js | 30 | async function assertLanguageEncodingFlagIs(expectedLanguageEncodingFlag, blobWriter) { | CODE |
| LOW | tests/all/test-keep-order-concurrent.js | 55 | async function testFailureDoesNotReorderOrPollute() { | CODE |
| LOW | tests/all/test-end-of-central-directory.js | 146 | function stuffWithUnreachableRecords(array, count) { | CODE |
| LOW | tests/all/test-end-of-central-directory.js | 186 | function countEndOfDirectorySignatures(array) { | CODE |
| LOW | tests/all/test-fs-import-edge-cases.js | 23 | async function testDirectoryWithoutSlash() { | CODE |
| LOW | tests/all/test-fs-import-edge-cases.js | 41 | async function testImplicitDirectoryMetadata() { | CODE |
| LOW | tests/all/test-fs-import-edge-cases.js | 53 | async function testExplicitDirectoryMetadata() { | CODE |
| LOW | tests/all/test-fs-import-edge-cases.js | 93 | async function testReadOptionsPrecedence() { | CODE |
| LOW | lib/zip-module-wasm.js | 60 | function terminateWorkersAndModule() { | CODE |
| LOW | lib/core/zip-fs.js | 978 | async function transformToFileSystemhandle(entry) { | CODE |
| LOW | lib/core/zip-fs.js | 995 | async function transformToFileSystemhandles(entry) { | CODE |
| LOW | lib/core/zip-reader.js | 960 | function readExtraFieldExtendedTimestamp(extraFieldExtendedTimestamp, directory, localDirectory) { | CODE |
| LOW | lib/core/zip-reader.js | 1108 | async function findEndOfCentralDirectory(reader, rejectAmbiguous, maxAppendedDataSize) { | CODE |
| LOW | lib/core/zip-reader.js | 1167 | async function seekEndOfCentralDirectory(reader, maxAppendedDataSize, remoteProbeBudget) { | CODE |
| LOW | lib/core/zip-reader.js | 1207 | async function getCentralDirectoryReachability(reader, view, anchoredOffset, indexByte, offset, size, remoteProbeBudget) | CODE |
| LOW | lib/core/zip-writer.js | 999 | function requestLockCurrentFileEntry() { | CODE |
| LOW | lib/core/zip-writer.js | 1729 | async function writeEndOfDirectoryRecord(zipWriter, comment, options, cdInfo) { | CODE |
| LOW | lib/core/streams/zip-entry-stream.js | 221 | function pipeThroughCommpressionStream(readable, useCompressionStream, options, CompressionStreamNative, CompressionStre | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| HIGH | lib/core/codec-worker.js | 199 | // supplied through config (e.g. the pure-JS port) stays usable and is kept as requested. | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | README.md | 41 | COMMENT | |
| LOW | README.md | 101 | // Creates a ZipWriter object writing data into `zipFileStream.writable`, adds | COMMENT |
| LOW | benchmarks/bench-crc.js | 1 | // Write-path CRC strategy, native CompressionStream. Compares the two ways zip.js can obtain the | COMMENT |
| LOW | lib/core/util/opfs-temp-stream.js | 41 | // It is meant for the buffered-write path (keep-order concurrent `add()`, non-seekable output, ...), | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | lib/core/zip-reader.js | 518 | async function getData() { | CODE |