Error: output buffer too small

[hxfdarling]

I want to transfrom wav to mp3 ,but i got an error Error: output buffer too small

let 	lame = require('lame')
const wav = require('wav')
const fs = require('fs')

function wav2mp3(input, output, next = function() {}) {
	const rs = fs.createReadStream(input)
	const ws = fs.createWriteStream(output)
	const reader = new wav.Reader()

	// the "format" event gets emitted at the end of the WAVE header
	reader.on('format', function(format) {
		const encoder = new lame.Encoder({
			// input
			channels: format.channels, // 2 channels (left and right)
			bitDepth: format.bitDepth, // 16-bit samples
			sampleRate: format.sampleRate, // 44,100 Hz sample rate

			// output
			bitRate: 128,
			outSampleRate: 22050,
			mode: lame.STEREO // STEREO (default), JOINTSTEREO, DUALCHANNEL or MONO
		})
		// the WAVE header is stripped from the output of the reader
		reader.pipe(encoder)
		encoder.pipe(ws)
	})
	// pipe the WAVE file to the Reader instance
	reader.on('finish', () => {
		rs.close()
		ws.close()
		next(null);
	})
	rs.pipe(reader)
}
wav2mp3('./xxx.wav', './xxx.mp3', (err) => {
	console.log('success')
})

files

xxx.zip