Route Instance

Let's rewrite our cities routes using a Route Instance.

Create a new Route Instance for the '/cities' URL path and assign it to thecitiesRoute variable.

var citiesRoute = app.route('/cities');

Move the code from our previous app.get() route to a new GET route on the citiesRoute object.

// GET route for /cities
citiesRoute.get(function (request, response) {
if(request.query.search) {
response.json(citySearch(request.query.search));
} else {
response.json(cities);
}
});

Move app.post() to citiesRoute.

// POST route for /cities
citiesRoute.post(parseUrlencoded, function (request, response) {
if(request.body.description.length > 4) {
var city = createCity(request.body.name, request.body.description);
response.status(201).json(city);
} else {
response.status(400).json('Invalid City');
}
});

Now, let's get rid of the citiesRoute temporary variable and use chaining function calls.

app.route('/cities')
.get(function (request, response) {
if(request.query.search) {
response.json(citySearch(request.query.search));
} else {
response.json(cities);
}
})
.post(parseUrlencoded, function (request, response) {
if(request.body.description.length > 4) {
var city = createCity(request.body.name, request.body.description);
response.status(201).json(city);
} else {
response.status(400).json('Invalid City');
}
});

Finally, let's move the old routes for the '/cities/:name' URL path to use the new Route Instance API.

app.route('/cities/:name')
.get(function (request, response) {
var cityInfo = cities[request.cityName];
if(cityInfo) {
response.json(cityInfo);
} else {
response.status(404).json('City not found');
}
})
.delete(function (request, response) {
if(cities[request.cityName]) {
delete cities[request.cityName];
response.sendStatus(200);
} else {
response.sendStatus(404);
}
});

Before:

var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var parseUrlencoded = bodyParser.urlencoded({ extended: false });
// In memory store for the cities in our application
var cities = {}; var citiesRoute; // GET route for /cities
app.get('/cities', function (request, response) {
if(request.query.search) {
response.json(citySearch(request.query.search));
} else {
response.json(cities);
}
}); // POST route for /cities
app.post('/cities', parseUrlencoded, function (request, response) {
if(request.body.description.length > 4) {
var city = createCity(request.body.name, request.body.description);
response.status(201).json(city);
} else {
response.status(400).json('Invalid City');
}
}); // GET route for /cities/:name
app.get('/cities/:name', function (request, response) {
var cityInfo = cities[request.cityName];
if(cityInfo) {
response.json(cityInfo);
} else {
response.status(404).json('City not found');
}
}); // DELETE route for /cities/:name
app.delete('/cities/:name', function (request, response) {
if(cities[request.cityName]) {
delete cities[request.cityName];
response.sendStatus(200);
} else {
response.sendStatus(404);
}
}); // Searches for keyword in description and returns the city
function citySearch(keyword) {
var result = null;
var search = RegExp(keyword, 'i');
for(var city in cities) {
if(search.test(cities[city])) {
return city;
}
}
} // Adds a new city to the in memory store
function createCity(name, description) {
cities[name] = description;
return name;
} app.listen(3000);

Now:

var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var parseUrlencoded = bodyParser.urlencoded({ extended: false });
// In memory store for the cities in our application
var cities = {}; app.route('/cities')
.get(function (request, response) {
if(request.query.search) {
response.json(citySearch(request.query.search));
} else {
response.json(cities);
}
})
.post(parseUrlencoded, function (request, response) {
if(request.body.description.length > 4) {
var city = createCity(request.body.name, request.body.description);
response.status(201).json(city);
} else {
response.status(400).json('Invalid City');
}
}); app.route('/cities/:name')
.get(function (request, response) {
var cityInfo = cities[request.cityName];
if(cityInfo) {
response.json(cityInfo);
} else {
response.status(404).json('City not found');
}
})
.delete(function (request, response) {
if(cities[request.cityName]) {
delete cities[request.cityName];
response.sendStatus(200);
} else {
response.sendStatus(404);
}
}); // Searches for keyword in description and returns the city
function citySearch(keyword) {
var result = null;
var search = RegExp(keyword, 'i');
for(var city in cities) {
if(search.test(cities[city])) {
return city;
}
}
} // Adds a new city to the in memory store
function createCity(name, description) {
cities[name] = description;
return name;
} app.listen(3000);

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