Cannot read property 'length' of undefined (Average Band Powers) about bci.js

[pwstegman]

Thanks for letting me know, I'll look into this. Could you add the code you ran that caused the error?

[yahyawasim97]

const bci = require('bcijs');

let samples;
const getData =async()=>{
let a = await bci.loadEDF('awais.md.edf');
samples =[...a.channels[0].samples];
console.log(a)
try{

        let feature = await bci.averageBandPowers(a.channels, 256, ['alpha','beta']);
        console.log(feature);
    }catch(e){
        console.log(e)
    }

}
getData();

[pwstegman]

Looks like the documentation for loadEDF needed updating. I've corrected it now. Each channel is an object that has a 1D array of samples for that channel, so passing a.channels into averageBandPowers will throw an error. I've modified your code to get it working. Give this a try:

const bci = require('bcijs');

let samples;

const getData = () => {
    let edf = bci.loadEDF('awais.md.edf');

    // Grab the samples from each channel
    samples = edf.channels.map(channel => channel.samples);

    // Transpose so channels are columns and samples are rows (the format averageBandPower expects)
    samples = bci.transpose(samples);
    
    let feature = bci.averageBandPowers(samples, 256, ['alpha','beta']);
    console.log(feature);
}

getData();

[yahyawasim97]

Thanks alot man! It works!