Function loadCompiler

typescript/verify.js:49–66

* Loads the TypeScript compiler a project asks for. * * A project pins an older release by naming it in the `typescript` field of * its own `package.json`; the release itself is installed under an npm alias * in this directory's `package.json`. Everything else compiles with the * version the re

(directory)

 * @returns {Promise<typeof ts>} The compiler to use.
 */
async function loadCompiler(directory) {
  let manifest = path.join(directory, 'package.json');
  let contents;

  try {
    contents = await fs.readFile(manifest, { encoding: 'utf8' });
  } catch (ex) {
    if (ex.code === 'ENOENT') {
      return ts;
    }

    throw ex;
  }

  let pinned = JSON.parse(contents).typescript;

  return pinned ? require(pinned) : ts;
}

/**
 * Verifies that a TypeScript project compiles.