I have the following test application based on a template provided by openshift.
server.js:
var express = require('express');
exports.NodeTestApp = function () {
self.cache_get = function (key) {
return 'Would be a value here';
};
}
server_test.js:
var server = require('../server');
describe('Server', function(){
describe('Startup',function(){
it('sets up routes during startup',function(){
var app = server.NodeTestApp();
app.cache_get('/');
expect(app.routes.size).to.equals(5);
})
})
})
When I run this test I get an error message that cache_get is not defined.
TypeError: Cannot read property 'cache_get' of undefined
at Context.<anonymous> (test/server_test.js:7:16)
I would have thought that everything that is specified in the NodeTestApp function is available via variable app. IntelliJ even shows me the function as a valid call. Any idea why I get this error ?
Thanks in advance.
Oliver
I figured out the problem with above code. To instantiate the app variable the new keyword has to be used. I didn't think that this is required as I would have thought its purely a function call and not a constructor call, which requires the new keyword. Below is the working code for your reference.
var app = new server.NodeTestApp();
Related
In this code snippet:
Const express = require('express')
Const app = express();
/*Typeof express = function
Typeof app = function*/
app.get()
My question is: if app is a function then how can we use a dot operator with it to call get function, and if we are creating a object of function express then why didn't we use new keyword to create an object.
Secondly, module.exports exports the literals in object format then why we are getting typeof express here a function.
If I am wrong anywhere, please correct me.
In JavaScript functions are objects, so this is valid:
function x() {
console.log("this is x()");
}
x.y = function() {
console.log("this is x.y()");
}
x();
x.y();
Express and other JavaScript tools use this feature extensively.
If you're used to other languages where functions are just functions and not objects themselves this will seem extraordinarily strange.
maybe someone have example for creating small API on node.js
Example, i have function this function will return string
I need call this string from postman or inside any another project with http.
What better for create this API?
Maybe someone know good guide? I worked before with node.js only like web-server
It is best practice that building API's in nodejs with express.Here is a code in which function returns a string. You need to export it. And require the file that contains exported value in your project file with the file path. Here is my function code where I am returning a string value. func.js
var string;
function myfunc(param,callback){
var str="hello";
callback(null,str);
}
myfunc('aaa',function(err,result){
if(err){
console.log(err);
}
else{
exports.string=result;
}
});
Here is my routes file and here I am calling the string from func.js and I named this file as str.js
var http = require('http');
var express = require('express');
var main = require('./func.js');//path of file
var org = main.string;
var app = express();
app.get('/str',function(req,res){
console.log(org);
res.send(org);
});
app.listen(3000,function(){
console.log("Server listening on 3000");
});
Run the code as node str.js and in postman run the url as http://localhost:3000/str and you can see the returned string in both response and in terminal.
Hope this helps...
This tutorial shows you how to build an API in Node.js with Express.
EDIT: You can skip the database part if you don't need it.
I wrote the following code in nodejs:
var express = require('express');
var app = express();
app.message = "helloworld";
app.get('/check', function (req,res) {
res.end("GET request OK");
console.log(this.message);
});
app.listen(4000);
When I run the code and send a GET request, the line:
console.log(this.message);
prints "undefined".
However, when I change it to:
console.log(app.message)
I get "helloworld".
I thought that this variable should represent the object that invoked the function. If so, why doesn't this object include the attribute .message ?
this can be whatever the author of the library intends it to be. It could be the app instance or it could be the global object.
In this case, it appears it's the global object.
As a sidenote too, it's not recommended to add expando properties to an existing library like that.
I started a new project from scratch with ExpressJS.
Everything works fine but now I begin to have a dozen of 'app.get(....)' function and I need to give the project a structure.
What I have in mind is quite simple, it should have a folder named 'routes' containing a file such as 'module1.js', with all of the app.get related to that module. (like I've seen in many examples)
The issue is how to tell Express to route 'http://url/module1/' to that route file and how to pass it a param variable, containing for instance the mongodb connection.
what I tried is :
var params = {
db: myMongoConnection
};
var mod1 = require('routes/module1');
app.use('/module1', mod1);
but now I still miss the 'params'.
If I try to pass it as an argument to the require method i get an error saying it needs middleware.
Another issue is related to the fact that the myMongoConnection is valid in the connection callback, so I think i need to require and use the route.js inside the MongoClient connect callback.
Any idea?
thanks a lot
For custom modules, create a folder, call it modules
In its index.js, expose the modules that you need.
Something like,
var mods = [
'mod1',
'mod2',
];
function init() {
var expose = {};
var params = {
db: myMongoConnection
};
mods.forEach(mods, function (mod) {
expose[mod] = require('./' + mod)(params);
});
return expose;
}
// export init
module.exports = init;
In mod1.js, wrap the params
module.exports = function(params) {
// all your functions here will have access to params.
}
Then in, server/app.js, require this and set it in the app.
app.set('mods', require('path-to/modules'));
Now, you can access all your modules, using app.get('mods').moduleName.methodname
I don't know how I'd term this maybe 'static call to a koa router'? Does that seem like the right wordage here for what I'm really trying to accomplish if you were to talk about it technically?
Anyway, I'm using koa-router and I'm coding unit tests (not integration tests). So I do not want to invoke .listen() on my koa app because of that reason...it would create an http server which now makes my test an integration tests.
Instead in my test I simply want to make a straight call to the app object instance and call a route and be able to return no results and check that I returned no results in the response.
How can you do that? I can't find an example and I've tried all sorts of pseudo code attemps agains the koa app object.
If you want to test the function that koa-router routes to then just perform a unit test on that function and leave the routing out of it.
To me it sounds like you've got a file such as app.js and it contains all your code. What you can do is create a router.js file to put you route bindings and a services.js file where you can put your application logic.
So for example app.js might look like:
var koa = require("koa");
var app = module.exports = koa();
var router = require('./router.js');
app.use(router.unsecured.middleware());
app.listen(3000);
And router.js might look like:
var router = require("koa-router");
var service = require("./services.js");
var unsecured = module.exports.unsecured = new router();
unsecured.post('/account/signin', service.signinUser);
unsecured.post('/account/register', service.registerUser);
And services.js might look like:
module.exports.signinUser = function*(signinDetails) {
// contains your application signin logic
};
module.exports.registerUser = function*(registerDetails) {
// contains your application register logic
};
So in this manner you can individually test services.js. I don't see any value in individually testing router.js since it is so trivial. As #Dan Pantry shows you can test routing as part of an integration test using supertest.
Edit:
So this is a little experimental test I was playing around with to test that the routing is correct. I'm using mocha as the test runner and the code example I posted in my original code.
// standard library
var assert = require("assert");
// in app objects
var router = require('./router.js');
var service = require('./service.js');
describe("routing tests", function() {
it("test register routing, POST", function*(done) {
// arrange
var unsecured = router.unsecured;
var path = '/account/register';
var httpMethod = 'POST';
var expected = service.register.toString();
var actual;
// act
for (var i = 0; i < unsecured.stack.length; i++)
{
var pathMatch = unsecured.stack[i].path === path;
var methodMatch = unsecured.stack[i].methods.indexOf(httpMethod) >= 0;
if (pathMatch && methodMatch)
{
actual = unsecured.stack[i].middleware.toString();
break;
}
}
// assert
try {
assert.equal(expected, actual);
done();
} catch(err) {
done(err);
}
});
});
There is probably a neater way of doing this (and a more modular way for testing multiple paths) but as I said this is just a basic example to verify the routing is calling the correct service. What I'm doing is delving into the koa-router object to verify what path is bound to what service code depending on the HTTP method (e.g. POST, GET, etc).
If you have your routing and your services in modules this test completely avoids dealing with the main koa app. Although technically this test spans multiple units (the routing and the service code) so it would technically be an integration test but it does mean you don't go near app.listen() which is what you didn't want to call in your tests.