server.js

const PORT = 8000
const express = require('express')
const cors = require('cors')
const app = express()
app.use(express.json())
app.use(cors())

const API_KEY="sk-E7ta3zLBuLZkv...FmRSpGvV"

app.post('/completions' , async (req, res) =>{
    const options={
        method:"POST",
        headers:{
            "Authorization": `Bearer ${API_KEY}`,
            "Content-Type":"application/json"
        },
        body: JSON.stringify({
            model : "gpt-3.5-turbo",
            messages: [{role:"user", content: req.body.message}],
            max_tokens: 100,
        })
    }
    try {
        const response = await fetch('https://api.openai.com/v1/chat/completions', options)
        const data = await response.json()
        res.send(data)
    } catch(error){
        console.log(error)
     }
})

app.listen(PORT, () => console.log('YOUR SERVER IS RUNNING ON PORTland: '+PORT))