Function getNodeVersionFromFile

src/util.ts:8–73

(versionFilePath: string)

import path from 'path';

export function getNodeVersionFromFile(versionFilePath: string): string | null {
  if (!fs.existsSync(versionFilePath)) {
    throw new Error(
      `The specified node version file at: ${versionFilePath} does not exist`
    );
  }

  const contents = fs.readFileSync(versionFilePath, 'utf8');

  // Try parsing the file as an NPM `package.json` file.
  try {
    const manifest = JSON.parse(contents);

    // Presume package.json file.
    if (typeof manifest === 'object' && !!manifest) {
      // Support Volta.
      // See https://docs.volta.sh/guide/understanding#managing-your-project
      if (manifest.volta?.node) {
        return manifest.volta.node;
      }

      // support devEngines from npm 11
      if (manifest.devEngines?.runtime) {
        // find an entry with name set to node and having set a version.
        // the devEngines.runtime can either be an object or an array of objects
        const nodeEntry = [manifest.devEngines.runtime]
          .flat()
          .find(({name, version}) => name?.toLowerCase() === 'node' && version);
        if (nodeEntry) {
          return nodeEntry.version;
        }
      }

      if (manifest.engines?.node) {
        return manifest.engines.node;
      }

      // Support Volta workspaces.
      // See https://docs.volta.sh/advanced/workspaces
      if (manifest.volta?.extends) {
        const extendedFilePath = path.resolve(
          path.dirname(versionFilePath),
          manifest.volta.extends
        );
        core.info('Resolving node version from ' + extendedFilePath);
        return getNodeVersionFromFile(extendedFilePath);
      }

      // If contents are an object, we parsed JSON
      // this can happen if node-version-file is a package.json
      // yet contains no volta.node or engines.node
      //
      // If node-version file is _not_ JSON, control flow
      // will not have reached these lines.
      //
      // And because we've reached here, we know the contents
      // *are* JSON, so no further string parsing makes sense.
      return null;