port of node's `require` for Scriptable.app

require-example.js

const require = importModule('scriptable-require')
const moment = await require('moment', true)
log(moment().format('dddd'))

scriptable-require.js

// Variables used by Scriptable.
// These must be at the very top of the file. Do not edit.
// icon-color: red; icon-glyph: magic;

// shared by hwangbible
// at: https://talk.automators.fm/t/tips-how-to-use-npm-modules-in-scriptable/5747

const fm = FileManager.iCloud();
const dir = fm.documentsDirectory();

const downloadIfNeeded = async (pkg, isAutoUpdateOn) => {
  let name = getPackageName(pkg);
  let filePath = fm.joinPath(dir, name + '.js');
  let isInstalled = await isFound(filePath);
  
  // If the package exists and autoupdate is off, stop checking further
  if (isInstalled && !isAutoUpdateOn) {
    console.log(`'${name}' is already installed, and autoupdate is disabled! Proceeding to import from disk...`);
    return;
  }
  
  // Get the package information which satisfies the given semver range
  let versionInfo = await getStatus(pkg);
  let versions = versionInfo.satisfied;
  let version = versionInfo.highest;

  // Download the newer version if necessary
  if (isInstalled && isAutoUpdateOn) {
    let installedVersion = await getInstalledVersion(name);
    // Check if the installed version satisfies the semver range
    if (versions.includes(installedVersion)) {
      console.log(`'${name}@${installedVersion}' satisfies the requested version. Good to go!`);
      return;
    } else {
      console.log(`'${name}@${installedVersion}' doesn't match the version requested. Reinstalling '${version}' now...`);
    }
  } else {
    console.log(`'${name}' was never installed previously. Downloading now...`);
  }

  // Download the package source and save to disk
  let source = await getPackageSource(pkg);
  savePackageToDisk(name, version, source);
};

const getInstalledVersion = async name => {
  // Read the version from {package}.ver
  let filePath = fm.joinPath(dir, name + '.ver');
  let version;
  if (isFound(filePath)) {
    let content = fm.readString(filePath);
    if (/^\d+\.\d+\.\d+$/g.test(content)) {
      version = content;
    }
  }
  console.log(`The installed version of '${name}' is ${version}.`);
  return version;
};

const getPackageSource = async pkg => {
  // Get the standalone package source from wzrd.in
  let request = new Request(`https://wzrd.in/standalone/${encodeURIComponent(pkg)}`);
  let response = await request.loadString();
  return response;
};

const getPackageName = pkg => {
  return pkg.split('@')[0];
};

const getStatus = async pkg => {
  // Retrieve the information about the package
  let request = new Request(`https://wzrd.in/status/${encodeURIComponent(pkg)}`);
  let response = await request.loadJSON();

  // Fail if the response is not good
  if (response.statusCode >= 400 || response.ok === false) {
    throw response.message;
  }

  // Fail if the semver did not satisfy any versions available on npm
  // Otherwise, sort the versions in descending order
  let versions = response.builds && Object.keys(response.builds);
  if (versions.length < 1) {
    throw `'${pkg}' did not satisfy any versions available on npm!`;
  } else {
    versions.sort((a, b) => b.localeCompare(a, undefined, { numeric: true }));
  }

  // Get all the satisfied versions and the highest version
  let result = {
    highest: versions[0],
    satisfied: versions,
  };

  return result;
};

const isFound = async filePath => {
  // Check if the package is already downloaded
  if (fm.fileExists(filePath)) {
    return true;
  }

  // Sync with iCloud and check again
  await syncFileWithiCloud(filePath);
  if (fm.fileExists(filePath)) {
    return true;
  }

  return false;
};

const savePackageToDisk = (name, version, source) => {
  // Write the package source and version info to disk
  let filename = fm.joinPath(dir, name);
  let jsFilePath = filename + '.js';
  let versionFilePath = filename + '.ver';
  let pkg = `${name}@${version}`;
  tryWriteFile(jsFilePath, source, pkg);
  tryWriteFile(versionFilePath, version, pkg);
  console.log(`Successfully installed ${name}@${version}!`);
};

const syncFileWithiCloud = async filePath => {
  // Try to sync with iCloud in case the package exists only on iCloud
  try {
    console.log(`Attempting to sync with iCloud just in case...`);
    await fm.downloadFileFromiCloud(filePath);
    console.log(`Finished syncing ${filePath}`);
  } catch (err) {
    console.log(`${filePath} does not exist on iCloud.`);
  }
};

const tryWriteFile = (path, content, pkg) => {
  // Sometimes wzrd.in is acting up and the file content is undefined.
  // So, here is a little trick to let you know what's going on.
  try {
    console.log(`Saving ${pkg} to disk at ${path}...`);
    fm.writeString(path, content);
  } catch (err) {
    throw `The package source from 'https://wzrd.in/standalone/${pkg}' is probably corrupted! Try with the different patch version.`;
  }
};

module.exports = async (pkg, isAutoUpdateOn = false) => {
  let name = getPackageName(pkg);
  await downloadIfNeeded(pkg, isAutoUpdateOn);
  return importModule(`${name}`);
};

Thanks for the reference. I've updated the script to mention the author and thread.

Thank you for sharing with us. When running the example on my iPad I get the following error:
Error: Data could not be read, they are not in the right format. (Translated from German)
Any ideas why this is the case?