Modern JavaScript Web Development Cookbook

Working with mocks

Let's finish by working with a more complex example—a part of the REST code that worked with regions, which requires a database and uses promises, among several complications. Let's take the DELETE method handler as an example:

const deleteRegion = async (    res: any,    dbConn: any,    country: string,    region: string) => {    try {        const sqlCities = `            SELECT 1 FROM cities             WHERE countryCode="${country}"             AND regionCode="${region}"             LIMIT 1         `;        const cities = await dbConn.query(sqlCities);        if (cities.length > 0) {            res.status(405).send("Cannot delete a region with cities");        } else {            const deleteRegion = `                DELETE FROM regions                 WHERE countryCode="${country}"                 AND regionCode="${region}"            `; const result = await dbConn.query(deleteRegion); ...