Build ~/.elm cache manually without checking SHA1 hashes

elm-build-cache.mjs

#!/usr/bin/env node

// the .mjs extension is important
// run this inside the directory containing the `elm.json` file
// (if it's not executable, run `chmod +x elm-build-cache.mjs`)
// with VERBOSE=1 env var it will show you results of the exec commands

import { promises } from "fs";
import { exec } from "child_process";
const fs = promises;
const tempDir = "elm-stuff/elm-build-cache";

const shouldLog = process.env.VERBOSE === "1"; // false; // true;
const ourExec = async cmd =>
  new Promise((resolve, reject) => {
    exec(cmd, (error, stdout, stderr) => {
      if (error) reject(error);
      if (shouldLog) console.log({ cmd, stdout, stderr });
      resolve([stdout, stderr]);
    });
  });

const downloadDependency = async ([pkg, version]) => {
  const pkgWithDash = pkg.replace("/", "-");

  const zipballUrl = `https://github.com/${pkg}/zipball/${version}/`;
  const zipballPath = `${tempDir}/${pkgWithDash}-${version}.zip`;

  // based on info in https://package.elm-lang.org/packages/elm/project-metadata-utils/latest/
  const elmHome = `~/.elm`;
  const packagePath = `${elmHome}/0.19.1/packages/${pkg}/${version}`;

  await ourExec(`mkdir -p ${tempDir}`);
  await ourExec(`rm -rf ${packagePath}`);
  await ourExec(`mkdir -p ${packagePath}`);
  await ourExec(`curl -L ${zipballUrl} -o ${zipballPath}`);
  await ourExec(`unzip ${zipballPath} -d ${tempDir}`);
  await ourExec(`mv ${tempDir}/${pkgWithDash}-*/* ${packagePath}`);
  await ourExec(`rm -rf '${zipballPath}'`);
};

const pickLowerBound = version => version.slice(0, version.indexOf(" "));
const getPackageDeps = elmJson =>
  Object.fromEntries(
    Object.entries(elmJson.dependencies).map(([k, v]) => [k, pickLowerBound(v)])
  );
const getAppDeps = elmJson => ({
  ...elmJson.dependencies.direct,
  ...elmJson.dependencies.indirect,
});
const getElmJsonDeps = elmJson =>
  elmJson.type === "application"
    ? getAppDeps(elmJson)
    : getPackageDeps(elmJson);

const main = async () => {
  await ourExec(`rm -rf '${tempDir}'`);

  const elmJson = JSON.parse(await fs.readFile("./elm.json", "utf-8"));
  const deps = getElmJsonDeps(elmJson);
  console.log({ deps });
  await Promise.all(Object.entries(deps).map(downloadDependency));

  await ourExec(`rm -rf '${tempDir}'`);
};