const read = require('as-buffer');
const stream = fs.createReadStream('./photo.png');
read(stream, { maxsize: 1e6 }) // with a max-size, default to 1e7, 10MiB
.then(buf => console.log('read', buf))
.catch(e => console.log('file too large'));
*: exception of object-mode streams that are returned as array
like https://github.com/stream-utils/stream-to-array but simpler