Language Support

Language	Status	Retrieval Quality
Python	Full	Benchmarked: 701 commits, 5 repos + 4 validation repos
TypeScript / JS (ESM)	Working prototype (`pip install -e ".[typescript]"`)	Mean recall 0–68% depending on code style — not one number
JavaScript (CommonJS)	Effectively unsupported	Measured 0.0% on express — do not use on CJS repos
Go / Rust / Java / others	Not supported	Retrieves nothing

Without the [typescript] extra installed, DiffContext is exactly the Python-only tool — no behavior change, no warnings.

TypeScript/JavaScript: Measured Results

Mined co-change cases (verify --from-history 25, the same harness you can run on your own repo):

Repo	Shape	Cases passed	Mean recall	Why
honojs/hono	ESM TS framework	19/25	67.9%	Clean relative-import graph
colinhacks/zod	TS monorepo, type-heavy	16/25	58.3%	Chained-generic style limits receiver typing
sindresorhus/ky	Small ESM TS lib	6/25	34.5%	History dominated by one mega-commit; cross-file type↔impl spread
expressjs/express	CommonJS JS	0/19	0.0%	CJS: `exports.x = function` yields almost no symbols

Retrieval quality tracks code style, not language. ESM TypeScript with a clear import graph lands in the same band as Python; CommonJS is a named, measured failure mode.

What the TS Adapter Resolves

Functions, class methods, arrow consts, namespaces
ES imports (named/default/namespace, aliases, barrel index.ts re-exports incl. export * from)
tsconfig/jsconfig baseUrl + paths aliases (@services/*)
this.method(), super(), new Class(), extends override edges
Function references passed as arguments
Declared-type resolution: parameter/field/local annotations and new X() inference make u.login(), this.db.query() resolve to the right class method

Still unresolved, disclosed: untyped receivers, tsconfig extends chains, CommonJS.

Known-Broken: The `verify` Score on TypeScript

⚠️

The verify sufficiency score has ZERO discriminating power on TypeScript today. On hono it reported 100 for every case while measured recall ranged 50–100% — that is not “uncalibrated,” it is a confidence signal that currently measures nothing for TS. Its structural inputs (direct-neighbor closure, parse health) were designed against Python graph density. On TS repos: run --calibrate, trust the recall numbers, ignore the score. TS-aware sufficiency inputs are roadmap work, and until they exist this warning stays here.

Exclusion Policy

Vendored/static JS inside Python repos (e.g. django’s admin jquery) is excluded by an adapter-level policy (static/, vendor/, *.min.*, colocated *.test.ts/*.spec.ts), so installing the extra does not pollute existing Python indexes.

Adapter Roadmap

TS-aware sufficiency inputs — the score currently has zero discriminating power on TS
CommonJS support — require(), exports.x =; the measured 0% failure mode
Per-language hybrid blend weights — current weights were tuned on Python graph density
Apply the five-repo benchmark methodology to TS
Further adapters (Go/Rust) via the diffcontext/languages/ template