I was learning APIs I have problem in POST AND PUT please anyone check this for me

@souvik88 can you help me please
I have problem in POST AND PUT please anyone check this for me

The JOI is returning error although I have given name: coursefour
also POST is not accepting my input of name: coursefour if i remove the validation part of JOI, it only increases the value of ID by 1 and not initilized the name with
req.body.name

const Joi = require('joi');
const express = require('express');
const app = express();

app.use(express.json());

const courses = [
    { id: 1, name: 'bca' },
    { id: 2, name: 'bba' },
    { id: 3, name: 'mba' },
];

// PROBLEM IN POST 

app.post('/api/courses', (req,res) => {
    const { error } =  validateCourse(req.body);
    if (error) return res.status(400).send(error.details[0].message);

    const course = {
        id: courses.length + 1,
                                   // PROBLEM IN POST 
        name: req.body.name
    };

    courses.push(course);
    res.send(course);
});


// PROBLEM IN PUT

app.put('/api/courses/:id', (req,res) => {
    const course = courses.find(c => c.id === parseInt(req.params.id));
    if(!course) return res.status(404).send('The Course with given id not found');
    
    const { error } =  validateCourse(req.body); // result.error
    if(error) return res.status(400).send(error.details[0].message);
    
    course.name = req.body.name;  
    res.send(course);               
});

function validateCourse(course) {
    const schema = {
        name: Joi.string().min(3).required()
    };
    return Joi.validate(course, schema);
}


const port = process.env.PORT || 8000;
app.listen(port, () => console.log(`Listening on port ${port}`));

POSTMAN SCREENSHOT

It looks like the problem is in the Postman request. Remember, key and value pairs need to be in double quotes for JSON.

{ "name": "coursefour" }