scc Integration¶

OCC uses scc (Succinct Code Counter) for code metrics. The integration is implemented in src/scc.ts. This page explains how scc is found, invoked, and integrated.

Binary Resolution¶

scc is located using a two-step fallback:

graph TD
    A[findScc] --> B{vendor/scc exists?}
    B -->|Yes| C[Use vendored binary]
    B -->|No| D{scc on PATH?}
    D -->|Yes| E[Use PATH binary]
    D -->|No| F[No scc available]

1. Vendored binary — vendor/scc (or vendor/scc.exe on Windows), downloaded during npm install
2. PATH fallback — if the vendored binary isn't found, OCC runs which scc (or where scc on Windows)

If neither is found, OCC throws an error (unless --no-code is used).

Postinstall Script¶

The scripts/postinstall.js script runs during npm install and downloads scc v3.7.0 from GitHub Releases.

Platform Support¶

Skipping the Download¶

Set SCC_SKIP_DOWNLOAD=1 to skip the automatic download:

SCC_SKIP_DOWNLOAD=1 npm install

The download is also skipped if the binary already exists at vendor/scc.

If the download fails (network issues, unsupported platform), the postinstall script exits gracefully — npm install still succeeds, and OCC falls back to PATH at runtime.

How scc Is Invoked¶

OCC runs scc as a subprocess via child_process.execFile (in src/scc.ts) with --format json to get structured output:

scc --format json \
    --exclude-ext docx,xlsx,pptx,pdf,odt,ods,odp \
    [--by-file] [--ci] [--no-gitignore] \
    [--exclude-dir <dir>]... \
    [-s <sort>] \
    <directories...>

Key details:

• Office extensions excluded — scc is told to skip all 7 office extensions so there's no overlap with OCC's document metrics
• JSON output — the raw JSON from scc is parsed and either rendered as a tabular code table or included in the JSON output
• Same flags forwarded — --by-file, --ci, --no-gitignore, --exclude-dir, and --sort are forwarded to scc
• Sort mapping — OCC's --sort words maps to scc's -s lines since scc doesn't have a "words" concept
• Timeout — scc is given a 60-second timeout and a 50 MB output buffer