Function fetchOnceAndSaveToDiskWithBuffer

mnist-node/data.js:44–61

(filename)

// Downloads a test file only once and returns the buffer for the file.
async function fetchOnceAndSaveToDiskWithBuffer(filename) {
  return new Promise(resolve => {
    const url = `${BASE_URL}${filename}.gz`;
    if (fs.existsSync(filename)) {
      resolve(readFile(filename));
      return;
    }
    const file = fs.createWriteStream(filename);
    console.log(`  * Downloading from: ${url}`);
    https.get(url, (response) => {
      const unzip = zlib.createGunzip();
      response.pipe(unzip).pipe(file);
      unzip.on('end', () => {
        resolve(readFile(filename));
      });
    });
  });
}

function loadHeaderValues(buffer, headerLength) {
  const headerValues = [];