# Contributor handoff — trekhleb/javascript-algorithms

> Canonical page: https://codevetter.com/unpack/javascript-algorithms/agent-handoff

# Contributor handoff — trekhleb/javascript-algorithms

Scanned commit 85293e3e2b88f4d2ce330d956b139cf628aa1e82 (2026-07-25). Generated by codevetter codevetter 1.12.0 on 2026-09-22.

Safe mental model: this is an educational algorithm catalog, not an app — optimize for clarity and pedagogy over cleverness or performance. Before editing, read CONTRIBUTING.md, .eslintrc, jest.config.js and the target module's README. Conventions: one default export per file, file name matches export (camelCase for functions, PascalCase for classes), heavy JSDoc typedefs and explanatory comments, co-located __test__ dirs, toString()-based assertions. Verify with npm test and npm run lint; keep 100% coverage or CI fails.
- Read first: CONTRIBUTING.md (PR rules: focused one-algorithm PRs, README required, 100% coverage), jest.config.js (testRegex + thresholds), .eslintrc (airbnb + relaxed rules), and the module's own README.md for the math/intent. — [CONTRIBUTING.md](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/CONTRIBUTING.md) [jest.config.js](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/jest.config.js) [.eslintrc](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/.eslintrc)
- House style: every module default-exports one function or class, annotates params/returns with JSDoc (including @typedef blocks for callback shapes), and explains non-obvious steps with inline comments — match this rather than introducing terse idioms. — [src/algorithms/image-processing/seam-carving/resizeImageWidth.js#L1-48](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/algorithms/image-processing/seam-carving/resizeImageWidth.js#L1-L48) [src/algorithms/graph/breadth-first-search/breadthFirstSearch.js#L4-14](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/algorithms/graph/breadth-first-search/breadthFirstSearch.js#L4-L14) [src/data-structures/linked-list/LinkedList.js#L18-21](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/data-structures/linked-list/LinkedList.js#L18-L21)
- Tests belong in a sibling `__test__` dir named <Module>.test.js; for shared algorithm families reuse the harness (SortTester statics) instead of duplicating fixtures. — [src/data-structures/linked-list/__test__/LinkedList.test.js](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/data-structures/linked-list/__test__/LinkedList.test.js) [src/algorithms/sorting/SortTester.js#L9-71](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/algorithms/sorting/SortTester.js#L9-L71)
- Run `npm test -- <pattern>` for a single module (e.g. 'playground'), `npm test` for the full suite, `npm run lint` before committing (husky does this anyway), and `npm run coverage` to check the CI gate locally. — [package.json#L30-36](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/package.json#L30-L36) [src/playground/playground.js#L6](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/playground/playground.js#L6) [.husky/pre-commit](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/.husky/pre-commit)
- Node >=22 and npm >=10 are required; dependencies are dev-only — do not add runtime dependencies, and prefer plain JS over new libraries since pedagogy is the product. (inferred) — [package.json#L37-53](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/package.json#L37-L53)
- Do not create index.js or try to 'package' the repo — the missing main entry is the status quo; consumers deep-import files like src/data-structures/linked-list/LinkedList.js. (inferred) — [package.json#L29](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/package.json#L29) [src/data-structures/linked-list/LinkedList.js](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/data-structures/linked-list/LinkedList.js)
- Mutating methods on data structures conventionally return `this` for chaining (append/prepend/insert/reverse); preserve that contract when editing or tests asserting chains will break. — [src/data-structures/linked-list/LinkedList.js#L22-55](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/data-structures/linked-list/LinkedList.js#L22-L55)
- When touching Comparator behavior, remember Comparator.reverse() mutates the compare function in place — several tests rely on reversing sort order via this mechanism. — [src/utils/comparator/Comparator.js#L78-81](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/utils/comparator/Comparator.js#L78-L81)
- The seam-carving test resolves PNG fixtures relative to process CWD (./src/...), so always run jest from the repo root; new file-IO tests should follow the `__tests__` plural dir convention so testRegex matches. — [src/algorithms/image-processing/seam-carving/__tests__/resizeImageWidth.node.js#L6-7](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/algorithms/image-processing/seam-carving/__tests__/resizeImageWidth.node.js#L6-L7) [jest.config.js#L22](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/jest.config.js#L22)
- Known traps: Graph throws on duplicate addVertex/addEdge (pre-check or expect the throw), HashTable keys must be strings (hash() iterates chars), and delete() on LinkedList removes ALL matching nodes, not just the first. — [src/data-structures/graph/Graph.js#L15-25](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/data-structures/graph/Graph.js#L15-L25) [src/data-structures/hash-table/HashTable.js#L27-45](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/data-structures/hash-table/HashTable.js#L27-L45) [src/data-structures/linked-list/LinkedList.js#L95-129](https://github.com/trekhleb/javascript-algorithms/blob/85293e3e2b88f4d2ce330d956b139cf628aa1e82/src/data-structures/linked-list/LinkedList.js#L95-L129)

Every claim links to its cited files at the pinned commit. Citations identify source evidence; they do not establish runtime correctness. Independent CodeVetter scan — not reviewed by upstream maintainers.

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