How to make module pattern each function a promise? - javascript

I use Angular 1.5 and I made a factory function which is return a literal object like this:
return {
item: null,
get: function() {
return item;
},
create: function() {
if (this.get()){
this.remove();
}
this.item = {};
},
remove: function() {
var item = this.get();
if (item) {
this.item = null;
}
},
add: function() {
if (!this.get()) {
this.create();
}
this.item.newprop = 'value';
}
}
please do not ask me to change to function declaration. I want a object with his own actions(functions) and properties that is working on.
This pattern (like get inside create so on..) I didn't copied from anywhere. so I'm wonder if has a name? It is best way to deal with function-black boxes?
What is the best way to put Promise inside? so every function should return a promise
every then function I need to use bind???
todo like this:
create: function () {
this.get()
.then(remove)
.then(function () {
this.item = {}; // BUT this === undefined!!
});
}

You have to use bind in every then callback function:
var myModule = {
item: null,
get: function() {
return Promise.resolve(this.item);
},
create: function() {
return this.remove().then(function() {
this.item = {};
}.bind(this));
},
remove: function() {
return this.get().then(function(item) {
if (item) {
this.item = null;
}
}.bind(this));
},
add: function() {
return this.get().then(function(item) {
return item || this.create();
}.bind(this)).then(function() {
this.item.newprop = 'value';
}.bind(this));
}
}
// Let see it working:
myModule.create().then(function() {
return myModule.get();
}).then(function(item) {
console.log("After create: ", item);
return myModule.remove();
}).then(function() {
return myModule.get();
}).then(function(item) {
console.log("After remove: ", item);
return myModule.add();
}).then(function() {
return myModule.get();
}).then(function(item) {
console.log("After add: ", item);
});

Related

JavaScript Proxy not working properly on ie11

I am building a simple validation library and I need to use Proxy because I want to accept custom validation rules as chain object. I build something and its works properly on modern browsers but not works on IE11, I tried with proxy-polyfill but its also not work properly. My proxy code is below.
function contextProxy(context) {
return new Proxy(context, {
get(obj, prop) {
if (prop in obj) {
return obj[prop];
}
const newContext = contextProxy(context._clone());
if (definedRules.hasOwnProperty(prop)) {
return newContext._takeRule(definedRules[prop]);
}
if (customRules.hasOwnProperty(prop)) {
return newContext._takeRule(customRules[prop]);
}
},
});
}
And I use that proxy;
function validationL() {
return contextProxy(new ValidationLContext());
}
And I have definedRules object;
const definedRules = {
numeric: function () {
return function (text) {
return /^\d+$/.test(text);
};
},
lowercase: function () {
return function (text) {
return /^([a-z]+\s*)+$/.test(text);
};
},
uppercase: function () {
return function (text) {
return /^([A-Z]+\s*)+$/.test(text);
};
},
minLength: function (min) {
return function (text) {
return text.length >= min;
};
},
maxLength: function (max) {
return function (text) {
return text.length <= max;
};
},
alphaNumeric: function () {
return function (text) {
return /^([a-zA-Z0-9 _-]+)$/i.test(text);
};
},
specialChars: function () {
return function (text) {
return !/^([a-zA-Z0-9 _-]+)$/i.test(text);
};
},
email: function () {
return function (text) {
return /^([a-zA-Z0-9_.+-])+\#(([a-zA-Z0-9-])+\.)+([a-zA-Z0-9]{2,4})+$/.test(
text
);
};
}
};
ValidationLContext.js
function ValidationLContext(isNot = false, chain = []) {
this.chain = chain;
this.isNot = isNot;
}
ValidationLContext.prototype.not = function () {
this.isNot = true;
return this;
};
ValidationLContext.prototype._takeRule = function (ruleFn) {
return (...args) => {
this.chain.push({ fn: ruleFn.apply(this, args), isNot: this.isNot });
if (this.isNot) {
this.isNot = false;
}
return this;
};
};
ValidationLContext.prototype.validate = function (text) {
return this.chain.every((c) =>
c.isNot ? !c.fn.call(this, text) : c.fn.call(this, text)
);
};
ValidationLContext.prototype._clone = function () {
return new ValidationLContext(this.isNot, this.chain);
};
export default ValidationLContext;
So library usage like this;
validationL().numeric().minLength(3).validate("123");
validationL().not().numeric().minLength(3).validate("123");
I can use like above on modern browsers like Chrome but when I try on IE11 only not() function works so only objects functions can work.
Can anyone help me with this.

How to define the getter function of an array in javascript Object.defineProperty?

I expect that I can get the list by the a.list, but this code does not work except using original value return.
function myclass() {
this._v = {
list: []
};
}
Object.defineProperty(myclass.prototype, 'list', {
get: function() {
// return this._v.list;
return this._v.list.map(val => {
console.log('val', val);
return val;
});
}
});
var a = new myclass();
a.list.push('abc');
console.log(a.list);
The getter is always returning a new empty array when called. When you push to it, there are no observable effects, because the array that's being changed isn't the array on the object.
You need to get a reference to the _v.list array so that you can push to it, which you can do either by reference it directly
function myclass() {
this._v = {
list: []
};
}
Object.defineProperty(myclass.prototype, 'list', {
get: function() {
return this._v.list.map(val => {
return val;
});
}
});
var a = new myclass();
a._v.list.push('abc');
console.log(a.list);
Or add a different method that returns the _v.list array:
function myclass() {
this._v = {
list: []
}
}
myclass.prototype.getArr = function() {
return this._v.list;
}
Object.defineProperty(myclass.prototype, 'list', {
get: function() {
return this._v.list.map(val => {
return val;
});
}
});
var a = new myclass();
a.getArr().push('abc');
console.log(a.list);
Maybe you wanted to push the elements in the _v.list and retrieve them from new list on myclass.
function myclass() {
this._v = {
list: []
};
}
Object.defineProperty(myclass.prototype, 'list', {
get: function() {
// return this._v.list;
return this._v.list.map(val => {
return val;
})
}
});
var a = new myclass();
a._v.list.push('abc');
console.log(a.list)
In your code you have overridden get method for list which is taking all its elements from _v.list but while pushing elements to list you are not pushing them to _v.list. That's why you are getting empty array which is _v.list not list.
'use strict';
function myclass() {
this._v = {
list: []
};
}
Object.defineProperty(myclass.prototype, 'list', {
get: function() {
// return this._v.list;
console.log('list', this._v.list);
return this._v.list.map(val => {
return val;
});
},
set: function(newVal) {
this._v.list.push(newVal);
}
});
const a = new myclass();
console.log(a);
a.list = 'abc';
console.log(a.list);

how nicely solve selenium promise? protractor

I wrote the following code (page object pattern). Works correctly.
However, I don't like this, because I can't remove "then" from "pressHelpLink". Instead add the code in getElementByLink.
I would like to see ElementFinder Promise (instead of ManagedPromise) as result of getElementByLink("Help")
How nicely solve selenium promise?
var self = Page.create({
url: {value: ''},
// function:
getElementByLink: {
value: function (link) {
return element.all(by.repeater('items')).then(function (el) {
var my_array = el.map(function (el) {
return el.element(self.by.xpath('a'));
});
var element_array_finder = protractor.ElementArrayFinder.fromArray(my_array);
var element = element_array_finder.filter(function (el) {
return el.getText().then(function (text) {
return text === link;
})
});
return element;
}).then(function (element) {
world.expect(element.length).equal(1);
return element[0];
});
}
},
// elements:
HelpLink: {
get: function () {
return self.getElementByLink('Help');
}
},
// method:
pressHelpLink: {
value: function () {
return self.HelpLink.then(function (el) {
return el.click()
});
}
},
});
Why not use cssContainingText? Maybe something like...
// elements:
HelpLink: {
get: function () {
return element(by.cssContainingText('a', 'Help');
}
},
// method:
pressHelpLink: {
value: function () {
return self.HelpLink.click()
}
},

Angularjs retain local variable

I have a factory like this:
TestFactory= function () {
var objectName=null;
return {
SetName:function(name) {
objectName = name;
},
GetName:function() {
return objectName;
},
Init:function() {
return angular.copy(this);
}
}
}
A controller like:
TestController = function($scope) {
$scope.TestClick = function () {
var tstA = TestFactory.Init();
var tstB = TestFactory.Init();
tstA.SetName('test A')
tstB.SetName('test B')
console.log('A', tstA.GetName());
console.log('B', tstB.GetName());
}
}
In the console I get Test B for both objects.
How can I make a proper instance of this object?
I would like to use the objectName value in other functions of the factory.
Take into account that in Angular, Factories are singletons, so the instance is always the same.
You can do the following:
TestFactory= function () {
var objectName={};
return {
SetName:function(property,name) {
objectName[property] = name;
},
GetName:function(property) {
return objectName[property];
},
Clear:function(property) {
delete objectName[property]
}
}
}
Then in your controller:
TestController = function($scope, TestFactory) {
$scope.TestClick = function () {
TestFactory.SetName('a','test A')
TestFactory.SetName('b','test B')
console.log('A', TestFactory.GetName('a')); // test A
console.log('B', TestFactory.GetName('b')); // test B
}
}
Couple of issues. First your returning an object rather than a function from your factory.
app.factory('TestFactory', function() {
return function() {
var objectName = null;
var setName = function(name) {
objectName = name;
};
var getName = function() {
return objectName;
};
return {
SetName: setName,
GetName: getName
};
};
});
Then you can just instantiate like this:
var tstA = new TestFactory();
var tstB = new TestFactory();
Services and factories are singletons so I think you can achieve what you want with a more appropriate use of the factory by providing an Init function that returns the common code and unique name like so:
angular.module('app')
.factory('ServiceFactory', serviceFactory);
function serviceFactory() {
return {
Init: function (name) {
return {
objectName: name,
setName: function (name) {
this.objectName = name;
},
getName: function () {
return this.objectName;
}
};
}
};
}
This leaves the possibility to use it as a factory that can initialize many types.
You basically need to create a simple getter/setter.
angular.module('app', [])
.controller('TestController', testController)
.service('serviceFactory', serviceFactory);
testController.$inject = ['serviceFactory'];
function testController(serviceFactory) {
serviceFactory.set('A', {
name: 'test A'
});
serviceFactory.set('B', {
name: 'test B'
});
console.log(serviceFactory.getAll());
console.log(serviceFactory.get('A'));
console.log(serviceFactory.get('B'));
}
function serviceFactory() {
var
_model = {
name: ""
},
_data = {};
return {
set: function(key, data) {
_data[key] = angular.extend({}, _model, data);
},
get: function(key) {
return _data[key];
},
getAll: function() {
return _data;
}
}
}
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.22/angular.min.js"></script>
<body ng-app="app" ng-controller="testController"></body>

How to prevent object properties to not be extended in javascript

Im trying to seal an object property .
My question is ,here i have given Object.seal(personObject),this particular object is sealed and does not allow to configure or make any extensions in this object,but as i did not mention on personObject_2 it does allow to extend or configure
How can i make it on prototype .I mean like any class of type person should have/respect this seal.Can we achieve such behaviour
"use strict";
var personModule=(function (module) {
var person=function (fname,lname) {
Object.defineProperty(this,'firstName',{
get:function () {
return fname;
}
,set:function (newValue) {
fname=newValue;
},
configurable:true
});
Object.defineProperty(this,'lastName',{
get:function () {
return lname;
}
,set:function (newValue) {
lname=newValue;
},
configurable:true
});
Object.defineProperty(this,'fullName',{
get:function () {
return fname+lname;
},
configurable:true
});
}
module.person=person;
return module;
})(personModule || {});
var personObject=new personModule.person( "Raju","Rani");
console.log(personObject.fullName);
Object.seal(personObject);
//delete personObject.firstName;-->It throws error here
var personObject2=new personModule.person( "Shiva","Kumar");
delete personObject2.firstName;
console.log(personObject2.firstName);
Thanks
Here is Proxy version in case you do not prefer adding Object.seal on constructor
"use strict";
var personModule=(function (module) {
var person=function (fname,lname) {
Object.defineProperty(this,'firstName',{
get:function () {
return fname;
}
,set:function (newValue) {
fname=newValue;
},
configurable:true
});
Object.defineProperty(this,'lastName',{
get:function () {
return lname;
}
,set:function (newValue) {
lname=newValue;
},
configurable:true
});
Object.defineProperty(this,'fullName',{
get:function () {
return fname+lname;
},
configurable:true
});
}
module.person=new Proxy(person, {
construct(target, args){
args.unshift(null);
let ctor = target.bind.apply(target, args);
let result = new ctor();
Object.seal(result);
return result;
}
});
return module;
})(personModule || {});
var personObject=new personModule.person( "Raju","Rani");
console.log(personObject.fullName);
Object.seal(personObject);
//delete personObject.firstName;-->It throws error here
var personObject2=new personModule.person( "Shiva","Kumar");
delete personObject2.firstName;
console.log(personObject2.firstName);
Did you tried - immutable-js
var personObject = new personModule.person("Raju", "Rani");
var sealed = Immutable.Map(personObject);

Categories