northwind-rest-api/backend/data-access-layer/dal.js

Local REST API Exposing Northwind Database.

const fs = require("fs");
const locations = require("../helpers/locations");

function getAllProducts() {
    return new Promise((resolve, reject) => {
        fs.readFile(locations.productsJsonFile, "utf-8", (err, fileContent) => {
            if (err) return reject(err);
            const products = JSON.parse(fileContent);
            resolve(products);
        });
    });
};

function saveAllProducts(products) {
    return new Promise((resolve, reject) => {
        const fileContent = JSON.stringify(products, null, 4);
        fs.writeFile(locations.productsJsonFile, fileContent, err => {
            if (err) return reject(err);
            resolve();
        });
    });
}

function getAllEmployees() {
    return new Promise((resolve, reject) => {
        fs.readFile(locations.employeesJsonFile, "utf-8", (err, fileContent) => {
            if (err) return reject(err);
            const employees = JSON.parse(fileContent);
            resolve(employees);
        });
    });
};

function saveAllEmployees(employees) {
    return new Promise((resolve, reject) => {
        const fileContent = JSON.stringify(employees, null, 4);
        fs.writeFile(locations.employeesJsonFile, fileContent, err => {
            if (err) return reject(err);
            resolve();
        });
    });
}

function getAllSuppliers() {
    return new Promise((resolve, reject) => {
        fs.readFile(locations.suppliersJsonFile, "utf-8", (err, fileContent) => {
            if (err) return reject(err);
            const suppliers = JSON.parse(fileContent);
            resolve(suppliers);
        });
    });
};

function saveAllSuppliers(suppliers) {
    return new Promise((resolve, reject) => {
        const fileContent = JSON.stringify(suppliers, null, 4);
        fs.writeFile(locations.suppliersJsonFile, fileContent, err => {
            if (err) return reject(err);
            resolve();
        });
    });
}

function getAllCategories() {
    return new Promise((resolve, reject) => {
        fs.readFile(locations.categoriesJsonFile, "utf-8", (err, fileContent) => {
            if (err) return reject(err);
            const categories = JSON.parse(fileContent);
            resolve(categories);
        });
    });
};

function saveAllCategories(categories) {
    return new Promise((resolve, reject) => {
        const fileContent = JSON.stringify(categories, null, 4);
        fs.writeFile(locations.categoriesJsonFile, fileContent, err => {
            if (err) return reject(err);
            resolve();
        });
    });
}

function getAllUsers() {
    return new Promise((resolve, reject) => {
        fs.readFile(locations.usersJsonFile, "utf-8", (err, fileContent) => {
            if (err) return reject(err);
            const users = JSON.parse(fileContent);
            resolve(users);
        });
    });
};

function saveAllUsers(users) {
    return new Promise((resolve, reject) => {
        const fileContent = JSON.stringify(users, null, 4);
        fs.writeFile(locations.usersJsonFile, fileContent, err => {
            if (err) return reject(err);
            resolve();
        });
    });
}

function getAllContactUsMessages() {
    return new Promise((resolve, reject) => {
        fs.readFile(locations.contactUsJsonFile, "utf-8", (err, fileContent) => {
            if (err) return reject(err);
            const users = JSON.parse(fileContent);
            resolve(users);
        });
    });
};

function saveAllContactUsMessages(users) {
    return new Promise((resolve, reject) => {
        const fileContent = JSON.stringify(users, null, 4);
        fs.writeFile(locations.contactUsJsonFile, fileContent, err => {
            if (err) return reject(err);
            resolve();
        });
    });
}

module.exports = {
    getAllProducts,
    saveAllProducts,
    getAllEmployees,
    saveAllEmployees,
    getAllSuppliers,
    saveAllSuppliers,
    getAllCategories,
    saveAllCategories,
    getAllUsers,
    saveAllUsers,
    getAllContactUsMessages,
    saveAllContactUsMessages
};