CODE EXAMPLE FOR JAVASCRIPT

crud in node

# Crud Operations
const db = require('./DB');
var dbInstance = new db();
const express = require('express');
const app = express();
const bodyparser = require('body-parser');
const port = process.env.PORT || 5000;
app.listen(port, () => console.log(`Listening on port ${port}..`));
//Configuring express server
app.use(bodyparser.json());
// Running express server
app.get('/', function (req, res) {
    res.send('Hello World!')
});
// Get all categories
app.get('/categories', function (req, res) {
    let categories = dbInstance.getCategories();
    categories.then((result) => {
        res.send(result);
    }).catch((err) => {
        res.send(err);
    });
});
// Get category by id
app.patch('/categories/:id', function (req, res) {
    let id = req.params.id;
    let category = dbInstance.getCategoryById(id);
    category.then((result) => {
        res.send(result);
    }).catch((err) => {
        res.send(err);
    });
});
// Add category
app.post('/categories', function (req, res) {
    let category = req.body;
    let addCategory = dbInstance.addCategory(category);
    addCategory.then((result) => {
        res.send(result);
    }).catch((err) => {
        res.send(err);
    });
});
// Update category
app.put('/categories/:id', function (req, res) {
    let id = req.params.id;
    let category = req.body;
    let updateCategory = dbInstance.updateCategory(id, category);
    updateCategory.then((result) => {
        res.send(result);
    }).catch((err) => {
        res.send(err);
    });
});
// Delete category
app.delete('/categories/:id', function (req, res) {
    let id = req.params.id;
    let deleteCategory = dbInstance.deleteCategory(id);
    deleteCategory.then((result) => {
        res.send(result);
    }).catch((err) => {
        res.send(err);
    });
});