sineWave = {
const waveForm = (td, len) => d3.range(len).map( n => {
const TAU = Math.PI * 2
const x = (n * seconds) / (len - 1)
const timeStamp = (td / 1000 - x)
const y = Math.sin(timeStamp * TAU * frequency)
return [x, y]
})
const t0 = Date.now()
while (true) {
const timeDelta = Date.now() - t0
yield Promises.delay(5, waveForm(timeDelta, streamLength))
}
}