why numchannels is defined as 3, why use Int32Array

[DevTheKing]

1. why numchannels is defined as 3, why use Int32Array ??
2. what is the meaning of this line and why there is a constant value 4 ?
3. whats is req.file.buffer ?

[GantMan]

Which file are you looking at? I assume a demo?

[DevTheKing]

on this code for node js @GantMan

const express = require('express')
const multer = require('multer')
const jpeg = require('jpeg-js')

const tf = require('@tensorflow/tfjs-node')
const nsfw = require('nsfwjs')

const app = express()
const upload = multer()

let _model

const convert = async (img) => {
// Decoded image in UInt8 Byte array
const image = await jpeg.decode(img, true)

const numChannels = 3
const numPixels = image.width * image.height
const values = new Int32Array(numPixels * numChannels)

for (let i = 0; i < numPixels; i++)
for (let c = 0; c < numChannels; ++c)
values[i * numChannels + c] = image.data[i * 4 + c]

return tf.tensor3d(values, [image.height, image.width, numChannels], 'int32')
}

app.post('/nsfw', upload.single('image'), async (req, res) => {
if (!req.file) res.status(400).send('Missing image multipart/form-data')
else {
const image = await convert(req.file.buffer)
const predictions = await _model.classify(image)
image.dispose()
res.json(predictions)
}
})

const load_model = async () => {
_model = await nsfw.load()
}

// Keep the model in memory, make sure it's loaded only once
load_model().then(() => app.listen(8080))