I'm running into an issue with using RequireJS and Prototypal inheritance. Here's my module:
define(function () {
function Module(data) {
this.data = data;
}
Module.prototype.getData = function () {
return this.data;
};
Module.prototype.doSomething = function () {
console.log(this.data);
console.log(this.getData());
};
return Module;
Module.prototype.callFunction = function (fn) {
if (this[fn]) {
console.log('call');
Module.prototype[fn]();
}
};
});
Then I instantiate the module, like so:
var module = new Module({ name: 'Marty' });
module.getData(); // returns { name: 'Marty' }
module.data; // returns { name: 'Marty' }
module.callFunction('doSomething') // returns undefined on the first (and second) console log
The console.logs in the module.doSomething() always return undefined. Am I misunderstanding how prototypal inheritance works with RequireJS?
As it turns out, I had written the callFunction method incorrectly. The correct way is:
Module.prototype.callFunction = function (fn) {
if (this[fn] && typeof this[fn] === "function") {
this[fn]();
}
};
The problem was using Module.prototype instead of this. Whoops.
Related
I'm trying to implement native bind functionality. However, when I try to test it out, I'm not getting the expected output.
Can someone tell me where am I going wrong?
Function.prototype.myBind = function(...args) {
const self = this;
return function() {
return self.apply(this, args);
}
};
function demo() {
return {
name: 'James Bond',
printName: function (args) {
console.log(this.name, args);
}
};
}
const test = {
name: 'Aqua Man'
};
console.log(demo().printName.myBind(test)('2020'));
// expected
console.log(demo().printName.bind(test)('2020'));
You need to bind to argument like this:
Function.prototype.myBind = function(binder) {
const self = this;
return function() {
return self.apply(binder, arguments);
}
};
Following the Intern user guide, I wrote a simple page object:
define(function(require) {
function ListPage(remote) {
this.remote = remote;
}
ListPage.prototype = {
constructor: ListPage,
doSomething: function(value) {
return this.remote
.get(require.toUrl('http://localhost:5000/index.html'))
.findByCssSelector("[data-tag-test-id='element-of-interest']")
.click().end();
}
};
return ListPage;
});
In the test, I want to call doSomething twice in a row, like this:
define(function(require) {
var registerSuite = require('intern!object');
var ListPage = require('../support/pages/ListPage');
registerSuite(function() {
var listPage;
return {
name: 'test suite name',
setup: function() {
listPage = new ListPage(this.remote);
},
beforeEach: function() {
return listPage
.doSomething('Value 1')
.doSomething('Value 2');
},
'test function': function() {
// ...
}
};
});
});
However, when I run the test, I get this error:
TypeError: listPage.doSomething(...).doSomething is not a function
I tried some approaches described in this question, to no avail.
A better way to implement page objects with Intern is as helper functions rather than Command wrappers. Groups of related helper functions can then be used to create Page Object modules.
// A helper function can take config parameters and returns a function
// that will be used as a Command chain `then` callback.
function doSomething(value) {
return function () {
return this.parent
.findByCssSelector('whatever')
.click()
}
}
// ...
registerSuite(function () {
name: 'test suite',
'test function': function () {
return this.remote.get('page')
// In a Command chain, a call to the helper is the argument
// to a `then`
.then(doSomething('value 1'))
.then(doSomething('value 2'));
}
}
I'm fairly new to angularjs. I'm looking for a way to return objects for extending from a factory that ARE NOT singletons. This way, people can't muck with the object data higher up in the application stack. This is what I've come up with so far, is it correct? Or is there a better way?
angular.module('utils', [])
.factory('extendableOject', function () {
return function () {
return {
prop1 : 1,
func1 : function () {
this.prop1++;
}
};
} ();
});
Ok, I figured it out:
angular.module('utils', [])
.factory('extendableOject', function () {
return function () {
return {
prop1 : 1,
func1 : function () {
this.prop1++;
}
};
};
});
I should not have been invoking the function from within the factory. That would have been no different than just returning the object itself. With the above code, I can call "extendableObject()" from anywhere to retrieve a fresh instance.
Good day,
I have created an object that will manage data access. My app will be using a couple different datastores, so I have created a simple factory to switch between providers:
var dataProvider = {
company: {
getAllCompanies: function (callback) {
var impl = factory.createProvider(implInstance.current)
impl.company.getAllCompanies(callback);
}
}
projects: {
getAllProjects: function (callback) {
var impl = factory.createProvider(implInstance.current)
impl.projects.getAllProjects(callback);
}
}
}
That is all well and good, but I'd rather have my impl variable at the dataProvider level. I'm unsure how I would properly access it though, as 'this' doesn't provide me the right scope when I'm nested so deeply. I'd like something like the following:
var dataProvider = {
impl: function () { return factory.createProvider(implInstance.current) },
company: {
getAllCompanies: function (callback) {
//THIS WON'T WORK
this.impl.company.getAllCompanies(callback);
}
}
Thanks!
You'd want to use the module design pattern for this:
var dataProvider = (function () {
var getImpl = function () {
return factory.createProvider(implInstance.current);
};
return {
company: {
getAllCompanies: function (callback) {
getImpl().company.getAllCompanies(callback);
}
},
projects: {
getAllProjects: function (callback) {
getImpl().projects.getAllProjects(callback);
}
}
}
})();
I made a simple example of my problem with a babel object :
function babel(){
this.english = {
hello: function () { alert('hello'); },
goodbye: function () { alert('goodbye'); }
teeshirt: function () { alert('T-shirt'); }
}
}
Now, I want to extends this object :
babel.prototype.french = {
bonjour: function () { alert('bonjour'); },
aurevoir: function () { alert('au revoir'); }
}
But what if I need to use an existing function define before ?
babel.prototype.french = {
bonjour: function () { alert('bonjour'); },
aurevoir: function () { alert('aurevoir'); },
teeshirt: function () { this.english.teeshirt(); }
}
What I could do is :
var say = new babel();
(function (_this) {
babel.prototype.french = {
bonjour: function () { alert('bonjour'); },
aurevoir: function () { alert('aurevoir'); },
hello: function () { _this.english.hello(); }
}
})(say);
But in this case, I will always use the context of the say object, isn't it ?
The problem is, that in teeshirt function call this points to the french object, not babel object. If you have to access parent object, you should store reference to it somewhere. For example you can change your constructor like this:
function babel(){
this.english = {
parent: this,
hello: function () { alert('hello'); },
goodbye: function () { alert('goodbye'); }
teeshirt: function () { this.parent.french.something(); }
}
}
But as you can see, there is a problem if you don't create object in constructor. I don't see any 'nice' approach, but you can do this:
function babel(){
this.english = {
parent: this,
hello: function () { alert('hello'); },
goodbye: function () { alert('goodbye'); }
teeshirt: function () { this.parent.french.something(); }
};
for (var i in babel.prototype) {
this[i].parent = this;
}
}
Then your french will look like this:
babel.prototype.french = {
bonjour: function () { alert('bonjour'); },
aurevoir: function () { alert('aurevoir'); },
teeshirt: function () { this.parent.english.teeshirt(); }
}
While the question as asked does bring up all the fascinating issues with JavaScript's this and prototypal inheritance, I would suggest simplifying the whole problem and refactoring your objects. There are a couple ways to do this.
If the English version of teeshirt is the default, it should be in the object which is at the end of the prototype chain. That is, a French object would have as its prototype an English object. The French object would simply not contain a teeshirt member. This is similar to the way resource bundles work.
Now this idea may not work for you, because the relationship among the different bundles may be complex: perhaps sometimes Engish is a fallback sometimes but not other times. In this case, see if you can make your babel objects all singletons (i.e., just plain objects).
var babel = {}
babel.english = {
hello: function () { alert('hello'); },
goodbye: function () { alert('goodbye'); },
teeshirt: function () { alert('T-shirt'); }
}
babel.french = {
bonjour: function () { alert('bonjour'); },
aurevoir: function () { alert('aurevoir'); },
teeshirt: function () { babel.english.teeshirt(); }
}
babel.english.teeshirt();
babel.french.teeshirt();
Try it at http://jsfiddle.net/yRnLj/
I realize this looks like a complete avoidance of your interesting question. But if you only need one copy of each language bundle, it is a lot simpler. :-)