semver-compare.js

#!/usr/bin/env -S deno run
// LICENSE: MIT
// Copyright (C) 2021 Jan Christoph Ebersbach. All rights reserved.

import semverCompare from "https://cdn.skypack.dev/semver-compare?dts";
import sanctuary from "https://cdn.skypack.dev/sanctuary?dts";
const S = sanctuary;

const stripV = (s) => s.replace(/^v/, "");
const isVersion = (s) => s.match(/^v?[0-9]+(\.[0-9]+)*/) !== null;
const testArgs = (a) => a.reduce((acc, s) => acc && isVersion(s), true);

const extractVersions = (args) => {
  if (args.length === 3) {
    return [args[0], args[2]];
  }
  return args.slice(-2);
};

const _comp = (validResults) => (a, b) =>
  validResults.includes(semverCompare(a, b));
const cmp_predicates = {
  eq: _comp([0]),
  ge: _comp([0, 1]),
  gt: _comp([1]),
  le: _comp([0, -1]),
  lt: _comp([-1]),
};

if (Deno.args.length === 1 && S.elem(Deno.args[0])(["-v", "--version"])) {
  console.log(VERSION);
  Deno.exit(0);
} else if (
  ![2, 3].includes(Deno.args.length) ||
  !testArgs(extractVersions(Deno.args)) ||
  (Deno.args.length === 3 && !S.elem(Deno.args[1])(S.keys(cmp_predicates)))
) {
  console.log(`Reveived: semver-compare ${S.joinWith(" ")(Deno.args)}`);
  console.log(
    `Usage: semver-compare VERSION1 [${S.pipe([S.keys, S.joinWith("|")])(
      cmp_predicates
    )}] VERSION2`
  );
  console.log("Without predicate:");
  console.log("\texit code 0 if versions are equal");
  console.log("\texit code 1 if first versions is higher");
  console.log("\texit code 2 if first versions is lower");
  console.log(
    `With predicate [${S.pipe([S.keys, S.joinWith("|")])(cmp_predicates)}]:`
  );
  console.log(
    "\texit code 0 if predicate applies comparing VERSION1 to VERSION2"
  );
  console.log("\texit code 1 if predicate doesn't apply");
  console.log("Exit code 3 if an error occurs");
  Deno.exit(3);
}

let versions = extractVersions(Deno.args).map(stripV);
let exitcode = 3;

if (Deno.args.length === 2) {
  exitcode = semverCompare(...versions);
  if (exitcode === -1) {
    exitcode = 2;
  }
} else {
  const predicate = Deno.args[1];
  if (cmp_predicates[predicate](...versions)) {
    exitcode = 0;
  } else {
    exitcode = 1;
  }
}
Deno.exit(exitcode);