fftjs is a compact Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT) library for JavaScript. It implements the Cooley-Tukey radix-2 Decimation In Time (DIT) algorithm.
This package is available on npm.
npm install --save fftjs
The input can be either an array:
// must be a power of 2.
let signal = [0.13, -0.45, ....];Or an object consisting of a field named real
let signal = {
'real': [0.13, -0.45, ....]
};Then, you can compute the FFT like so:
const fftjs = require('fftjs');
let phasors = fftjs.fft(signal);
console.log("phasors: " + phasors);
/*
phasors: {
real: [...],
imag: [...]
};
*/phasors now contains the complex values in the ferquency domain representation of the signal!
We can also reconstruct our original time-domain signal from the complex phasors.
let reconstructedSignal = jsfft.ifft(phasors);
console.log("reconstructed signal: " + reconstructedSignal);
/*
reconstruted signal: [0.13, -0.45, ....];
reconstructedSignal should be identical to original signal (with very slight rounding errors caused by JavaScript)
*/
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