Async Gzip throws error saying to use Node 12+ but already running Node 14+

How to reproduce

The problem

Hi I’m trying to gzip some files in a .then() promise chain so I tried using gzipAsync() but received the following error:

Error: async operations unsupported - update to Node 12+ (or Node 10-11 with the --experimental-worker CLI flag)
    at Immediate.<anonymous> (file:///home/today/_/work/haptic/node_modules/fflate/esm/index.mjs:34:42)
    at processImmediate (internal/timers.js:456:21)

I’m running Node v14.2.0. The file is ESM via "type": "module" in package.json. The file imports fflate like this:

import esbuild from 'esbuild';
import { gzip, gzipSync } from 'fflate';
import { readFile, writeFile } from 'fs/promises';
// ...

Here’s the code that throws on L47:

If I replace L47 with res(gzipSync(readData, { consume: true, level: 9 })); then it’s fine. It’s also fast enough that I’m not reporting an issue with Sync vs Async, just that the error message might be wrong if it’s telling people to update to 12+.

Thanks!

[101arrowz]

Actually, all that error really means is “I couldn’t require the worker_threads package from the standard library,” which I assumed meant that you were in too old a version of Node. However, in this case the issue is probably that dynamic require doesn’t exist in an ESM environment. I’ll look into a solution, thanks for the report.

[101arrowz]

Yes, if the files are small (say under 300kB) typically the cost of creating a worker thread outweighs the benefit of concurrently compressing all the files at once. So I would suggest sticking with the sync version (but obviously the bug was something that needed to be fixed regardless). Thanks again for the report.