Function writeTsVersion

scripts/sync-ts-version.js:9–11

(tsVersion, filename)

 * @param {string} filename
 */
const writeTsVersion = (tsVersion, filename) => {
  fs.writeFileSync(filename, `export type TsVersion = "${tsVersion}";\n`);
};

const tsVersion = findTsVersion("yarn.lock");
if (tsVersion === undefined) {