FFmpeg with node.js. Transcode a file to another format

Have a bit of a problem with this, I have an .avi file in which I would like to transcode into a .flv file using FFmpeg, here is what I have so far:

var ffmpeg = require('fluent-ffmpeg');

//make sure you set the correct path to your video file
var proc = new ffmpeg({ source: 'C:/Users/Jay/Documents/movie/drop.avi', nolog: true })

//Set the path to where FFmpeg is installed
.setFfmpegPath("C:\Users\Jay\Documents\FFMPEG")

//set the size
.withSize('50%')

// set fps
.withFps(24)

// set output format to force
.toFormat('flv')

// setup event handlers
.on('end', function() {
    console.log('file has been converted successfully');
})
.on('error', function(err) {
    console.log('an error happened: ' + err.message);
})
// save to file <-- the new file I want -->
.saveToFile('C:/Users/Jay/Documents/movie/drop.flv');

It seems straightforward enough and I can do it through the FFmpeg command line, but I am trying to get it working within a node.js app, here is the error it is returning:

C:\Users\Jay\workspace\FFMPEGtest\test.js:17
.withSize('50%')
 ^
TypeError: Cannot call method 'withSize' of undefined
    at Object.<anonymous> (C:\Users\Jay\workspace\FFMPEGtest\test.js:17:2)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)
    at startup (node.js:119:16)
    at node.js:906:3

It throws the same error for each built in FFmpeg function (.toFormat, .withFPS etc)

If anyone has a solution to this, I'd greatly appreciate it

Solution

setFfmpegPath() doesn't return an instance of this, as seen in the source here. Meaning you can't chain the method.

Change it to

var ffmpeg = require('fluent-ffmpeg');

//make sure you set the correct path to your video file
var proc = new ffmpeg({ source: 'C:/Users/Jay/Documents/movie/drop.avi', nolog: true })

//Set the path to where FFmpeg is installed
proc.setFfmpegPath("C:\\Users\\Jay\\Documents\\FFMPEG")

proc
//set the size
.withSize('50%')

// set fps
.withFps(24)

// set output format to force
.toFormat('flv')

// setup event handlers
.on('end', function() {
    console.log('file has been converted successfully');
})
.on('error', function(err) {
    console.log('an error happened: ' + err.message);
})
// save to file <-- the new file I want -->
.saveToFile('C:/Users/Jay/Documents/movie/drop.flv');