score68

Date numerology enumerator: list dates whose (Day + Month + YY(first) + YY(last)) % 100 equals a target.

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Quick Start

Clone and run (private package, local usage):

git clone https://github.com/al-siv/score68.git
cd score68
npm install
npm run dates:68

Sample output excerpt:

Utility:  score68
Version:  <version>
Target:   68
Range:    01.01.2022–31.12.2026
2022: 25.01 24.02 23.03 ... 14.12
...
Total dates matching target '68': 60

Features

• Fixed default range: 2022-01-01..2026-12-31 (UTC)
• Custom target positional argument
• Explicit range flag (--range / -r)
• Dynamic last N years (--years / -y)
• Environment variable overrides (lower precedence than CLI)
• Pure computation module and thin CLI shell
• Property-based invariant test coverage

Formula

Raw sum:

Day + Month + (first two digits of year) + (last two digits of year)

Effective value: raw % 100.

Installation

Current state: private (not published to npm). Use clone method above. Planned publish path (if enabled later):

npm install score68
npx score68

CLI Usage

Commands / Examples

Purpose	Command
Default target 68	npm run dates:68
Custom target 69	node cli.js 69
Explicit range	node cli.js 68 --range 2000-01-01:2025-12-31
Explicit range (sh.)	node cli.js 68 -r 2000-01-01:2025-12-31
Last 10 years	node cli.js 68 -y 10
Help	node cli.js --help

Flags

Flag	Alias	Value	Description
--range	-r	YYYY-MM-DD:YYYY-MM-DD	Inclusive explicit date span
--years	-y	N	Last N full calendar years (ending current year)
--help	-h	–	Show help

Mutual exclusion: --range and --years cannot be combined.

Environment Variables

Lower precedence than CLI arguments.

Variable	Example	Meaning
SCORE68_TARGET	72	Numeric target (non-negative integer)
SCORE68_RANGE	2024-01-01:2024-12-31	Explicit range (overrides years)
SCORE68_YEARS	5	Last N years (ignored if range provided)

If both SCORE68_RANGE and SCORE68_YEARS are set, the range takes priority.

Exit / Error Behavior

Process exits with code 1 on invalid input. Example:

$ node cli.js --years 0
years must be positive integer

Error Codes (parser)

Code	Condition
UNKNOWN_FLAG	Unrecognized flag (not negative number)
INVALID_TARGET	Target positional not a non-negative integer
RANGE_FORMAT	--range value not matching pattern
RANGE_ORDER	Range start > end or invalid dates
YEARS_VALUE	--years value missing or non-positive integer
CONFLICT_RANGE_YEARS	Both range and years supplied

Programmatic API

Module: src/dates68.js (ESM). Example:

import { listDatesWithSum, numerologySum } from './src/dates68.js';

const matches = listDatesWithSum();           // default target (68) and default range
const alt = listDatesWithSum(69);             // alternate target
console.log(matches.length);

Function contract:

listDatesWithSum(target = 68, startDate = START_DATE, endDate = END_DATE) -> Date[]

Development

Task	Command
Install deps	npm install
Run all tests	npm test
Lint	npm run lint
Format	npm run format
Verify (lint + tests)	npm run verify

Node version: target modern LTS (>=18).

Release process: see docs/archive/BUILD_RELEASE-0.2.0.md.

Changelog

See CHANGELOG.md for version history.

Contributing

See CONTRIBUTING.md for author & maintainer workflows (branch naming, verification, PR template usage, merge & tag steps).

Non-goals

• Time zone localization (uses UTC internally)
• Alternative numerology formulas
• Output formatting customization beyond provided flags

License

CC0 1.0 Universal. See LICENSE.