Ashish Raina Ashish Raina - 24 days ago 12
Javascript Question

request-promise + co API trigger in protractor test

I want to call module.api.create from my protractor test. Referring this solution:-
Chain multiple Node http request I am using request-promise + co like this:-

//api/module1.js
var co = require('co');
var rp = require('request-promise');

exports.create = co(function* def() {
var response, token;
urlLogin.body.username = username;
response = yield rp(urlLogin);
//extract token and run other APIs
...
}).catch(err => console.log);


And

//api/api.js
var module1= require('./module1'),
exports.module1= function (){
return module1;
};


In my Spec/Test I am adding

api = require('../../api/api');
api.module1.create;


Issue i am facing is than even without calling the "api.module1.create;" line, the require line "api = require('../../api/api');" is calling the create automatically every-time the test is executed

Answer

From the co README:

co@4.0.0 has been released, which now relies on promises. It is a stepping stone towards the async/await proposal. The primary API change is how co() is invoked. Before, co returned a "thunk", which you then called with a callback and optional arguments. Now, co() returns a promise.

I believe you're looking for co.wrap, which returns a function that executes the generator and returns a promise (this function may also be known as a thunk). Using just co eagerly executes the generator and returns the result of executing the generator.

const co = require('co')

co(function* () {
  // this will run
  console.log('hello from plain co!')
})

co.wrap(function* () {
  // this won't run because we never call the returned function
  console.log('hello from wrapped co 1!')
})

const wrappedfn = co.wrap(function* () {
  // this runs because we call the returned function
  console.log('hello from wrapped co 2!')
})

wrappedfn()  

You can also wrap a function by yourself, which does the same thing as co.wrap and lets you do more stuff afterwards.

exports.create = function() {
  return co(function* () {
    // this will run only when exports.create is called
    console.log('hello from plain co!')
  })
  // If you want to do stuff after and outside the generator but inside the enclosing function
  .then(...)
}
Comments