cli API

The package Luna-Flow/mooncake-impact-factor/cli is an executable for the JavaScript target. It reads the eight signals of a score snapshot from a JSON file, calls compute_score_snapshot and prints the result as JSON. It exists so that programs outside MoonBit, above all the Python index builder, use the MoonBit score rules instead of copying them.

Source: src/cli/main.mbt. Its interface file is empty: the package exports no MoonBit names, and its interface is the command line described here.

Building

The package declares supported_targets = "js" and pkgtype(kind: "executable"). Build it from the repository root:

moon build src/cli --target js

The index builder expects the result at _build/js/debug/build/cli/cli.js and builds it when the file is missing. The script needs a Node.js version with process.getBuiltinModule (20.16, 22.3 or later).

score-snapshot

score-snapshot computes one score snapshot from a JSON input file.

node cli.js score-snapshot --input <path>

The first argument after the script must be score-snapshot. --input may appear anywhere after it; the first --input that is followed by a value wins, and other arguments are ignored.

Input

The file must contain one JSON object. Each key is optional:

Key	Signal
dependents	Current dependents.
recent_dependents	Current recent dependents.
downloads	Current downloads.
days_since_release	Days since the latest release, now.
historical_dependents	Dependents 30 days ago.
historical_recent_dependents	Recent dependents 30 days ago.
historical_downloads	Downloads 30 days ago.
historical_days_since_release	Days since the latest release, 30 days ago.

A value is used when it is a JSON number; it is converted to Int by truncation toward zero (12.9 becomes 12), and values beyond the Int range saturate at its bounds. A missing key, a value of any other JSON type (including a numeric string such as "20") and a top-level value that is not an object all count as 0. The score functions then clamp negative values to 0. Unknown keys are ignored.

{
  "dependents": 20,
  "recent_dependents": 4,
  "downloads": 300,
  "days_since_release": 40,
  "historical_dependents": 10,
  "historical_recent_dependents": 2,
  "historical_downloads": 0,
  "historical_days_since_release": 10
}

Output

On success the command prints one line, the JSON form of the ScoreSnapshot, and exits with status 0. Fields appear in declaration order. A NaN field, which only arises from a count of 2147483647 or more, is written as the string "NaN". For the input above the output is:

{"score":301.7852882193072,"score_30d_ago":135.2764584196223,"score_growth_30d":166.5088297996849,"score_growth_ratio_30d":1.2308780976744749,"rank_label":"S","momentum_label":"Rising","activity_multiplier":1.06}

Errors

Usage and parse errors print one JSON object with an error key to standard output and exit with status 1:

Situation	Output
No arguments, or the first argument is not score-snapshot	{"error":"Usage: score-snapshot --input <path>"}
No --input followed by a value	{"error":"Missing --input <path>"}
The file is not valid JSON	{"error":"Failed to parse JSON input"}

A file that cannot be read is not reported this way: Node.js raises an uncaught ENOENT (or similar) error, prints a stack trace to standard error and exits with status 1. Callers should treat any non-zero status as a failure and parse standard output only on status 0.