**Question**:- I have to calculate the FFT of time series data.

**Time series data of what ?**

I have a Vibration sensor that is giving me the data of displacement in x and y coordinate.

**What are the Problems?** I can’t find a proper library to work although I found some but I don’t know if it is working fine or not.

te

As far as I know, we need **Sample Rate** and **FFTsize**(number of elements) to calculate the FFT

I used the library https://www.npmjs.com/package/fft-js

in which I passed a 1D array and it returns a 2D array having some positive values and some negative values.

**Question I have**

*How does it calculate FFT without the sampling rate as far as I know a sampling rate is needed**For calculating FFT does data frequency need to be constant as like idealy I am having 170 data per second but sometime if goes down as 165 and 160**What are ways I can verify my fft*

Ps:- I am trying to plot fft in realtime

help or resource are much appreciated as I Can’t find any resource of fft in javascript

Source: Ask Javascript Questions