Use NPM Lock Versions

use_npm_lock_versions.js

#!/usr/bin/env node

// COMMAND: ./use_npm_lock_versions.js ~/path/to/your/repo

const fs = require('fs');
const os = require('os');

function init() {
  const directory = parseDirectory(process.argv.slice(2)[0]);
  const [packageJson, newlineCharacter] = loadPackageJson(directory);
  const packageLockJson = loadPackageLockJson(directory);
  const updatedPackageJson = updateVersions(packageJson, packageLockJson);
  savePackageJson(directory, updatedPackageJson, newlineCharacter);
}

function parseDirectory(dir) {
  return dir.replace('~', os.homedir);
}

function loadPackageJson(dir) {
  const fileContents = fs.readFileSync(`${dir}/package.json`, 'utf8');
  const newlineCharacter = detectNewlineAtEof(fileContents);
  return [ JSON.parse(fileContents), newlineCharacter ];
}

function loadPackageLockJson(dir) {
  return JSON.parse(fs.readFileSync(`${dir}/package-lock.json`, 'utf8'));
}

function savePackageJson(dir, json, newline) {
  const output = JSON.stringify(json, null, 2);
  fs.writeFileSync(`${dir}/package.json`, newline ? `${output}${newline}` : output);
}

function updateVersions(packageJson, packageLockJson) {
  const updatedPackageJson = {
    ...packageJson,
  };
  if (updatedPackageJson.devDependencies) {
    updatedPackageJson.devDependencies = updateDependencies(
      updatedPackageJson.devDependencies, packageLockJson
    );
  }
  if (updatedPackageJson.dependencies) {
    updatedPackageJson.dependencies = updateDependencies(
      updatedPackageJson.dependencies, packageLockJson
    );
  }
  return updatedPackageJson;
}

function updateDependencies(deps, packageLockJson) {
  const updatedDeps = {
    ...deps,
  };
  Object.keys(deps).forEach(dep => {
    updatedDeps[dep] = getPackageLockVersion(dep, updatedDeps[dep], packageLockJson);
  });
  return updatedDeps;
}

function getPackageLockVersion(dep, currentVersion, packageLockJson) {
  const isCurrentVersionExact = isVersionExact(currentVersion);
  const updatedVersion = packageLockJson.dependencies[dep].version;
  if (isCurrentVersionExact) {
    return updatedVersion;
  }
  if (updatedVersion === currentVersion.slice(1)) {
    return currentVersion;
  }
  return `~${updatedVersion}`;
}

function isVersionExact(version) {
  return /^\d/.test(version);
}

function detectNewlineAtEof(str) {
  const matches = str.match(/\r?\n$/);
  return matches ? matches[0] : null;
}

init();