I've tested only forward real-to-complex at this point (I haven't even checked that the inverse transforms produce the right results).
You can run these tests in a browser, either by checking out this repo and opening the file
fft/index.html or by navigating to this test page here.
- FFT by Nayuki (multilingual) - complex-complex
- FFT by Jens Nockert (also on npm) - real-complex and complex-complex
- JSFFT by Nick Jones - complex-complex, scales forward transform by 1/sqrt(n)
- KissFFT - modest C implementation, compiled with Emscripten
- Cross - minimal complex-complex C implementation, compiled with Emscripten
- FFTW - all-consuming C implementation, compiled with Emscripten