SOLUTION
Big shoutout to hege-hegedus for the helpful answer below. Implemented it in my code and it's working perfectly.
// NOTE: This function is called from another service, but I've removed some parts for brevity
// The serverObject being used is referred to as 'article'
var articleInstance = new Article(article);
console.log(articleInstance instanceof Article)
// true
console.log(articleInstance.isProduct(article))
// true (in my case)
/*
* Creating a constructor from the server article object using lodash
*/
ArticleConstructor.$inject = [];
function ArticleConstructor() {
return function(data) {
var keys = ['app_id', 'body', 'headline', 'object_type', 'url', 'status'
];
_.assign(this, _.pick(data, keys));
};
}
/*
* Extending the iief constuctor - ArticleConstructor
*/
Article.$inject = ['ArticleConstructor'];
function Article(ArticleConstructor) {
function ArticleExtended(data) {
ArticleConstructor.call(this, data);
}
// creating a new Article object with the ArticleConstructor prototype object and properties
ArticleExtended.prototype = Object.create(ArticleConstructor.prototype);
// making sure that Article inherits a constructor property from its prototype which is ArticleConstructor
ArticleExtended.prototype.constructor = ArticleExtended;
ArticleExtended.prototype.isProduct = function () {
return this.object_type == 3;
};
ArticleExtended.prototype.hasImage = function () {
return _.has(this, 'image');
};
return ArticleExtended;
}
I'm having trouble extending the factory object below. Although I'm using lodash to auto hydrate the factory constructor successfully, none of my original methods like isIcon() are executing properly. It gives an error message saying "isIcon is not a function." I've searched for solutions, but most of the constructor examples out there use the traditional return service; approach at the end of the object, which works fine but forces me to go back to a more manual way of building the constructor. I feel like I'm missing something obvious here.
I'm Using AngularJS 1.4.8
FACTORY OBJECT TO EXTEND
// This AJS factory seems to be causing issues
ImageUnableToExtendFn.$inject = ['IMG_TYPE'];
function ImageUnableToExtendFn(IMG_TYPE) {
Image.prototype.isIcon = function (img) {
return img.type === IMG_TYPE.ICON;
};
return function(data) {
var keys = ['id', 'src', 'alt', 'type'];
_.assign(this, _.pick(data, keys));
};
});
I've attempted to extend the IIEF factory with angular.extend(), however, that also doesn't work as expected (example provided below):
angular.extend(imageOfUnableToExtendFn, {
isIcon: function(img) {
return img.type === IMG_TYPE.ICON;
}
})
MORE DETAILED INFORMATION FOR REFERENCE
define([
'angular',
'lodash'
], function(angular, _) {
'use strict';
ImageService.$inject = ['ImageClassicFn', 'ImageUnableToExtendFn'];
function ImageService(ImageClassicFn, ImageUnableToExtendFn) {
var imageService = {
images: null,
createInstance: function(serverImageObject) {
var self = this,
imageOfClassicFn,
imageOfUnableToExtendFn,
isIcon;
if (angular.isDefined(serverImageObject)) {
imageOfClassicFn = new ImageClassicFn();
isIcon = imageOfClassicFn.isIcon(serverImageObject);
console.log('IS ICON', isIcon);
imageOfUnableToExtendFn = new ImageUnableToExtendFn(serverImageObject);
isIcon = imageOfClassicFn.isIcon(serverImageObject);
angular.extend(imageOfUnableToExtendFn, {
isIcon: function(img) {
return img.type === IMG_TYPE.ICON;
}
})
isIcon = imageOfClassicFn.isIcon(serverImageObject);
}
}
};
return imageService;
}
// Factory for Classic Image Functionality
ImageClassicFn.$inject = ['IMG_TYPE'];
function Image(IMG_TYPE) {
function Image(id, src, alt, type) {
this.id = id;
this.src = src;
this.alt = alt;
this.type = type;
}
Image.prototype.isIcon = function (img) {
return img.type === IMG_TYPE.ICON;
};
return Image;
});
// Factory for Unable To Extend Image Functionality
ImageUnableToExtendFn.$inject = ['IMG_TYPE'];
function Image(IMG_TYPE) {
Image.prototype.isIcon = function (img) {
return img.type === IMG_TYPE.ICON;
};
return function(data) {
var keys = ['id', 'src', 'alt', 'type'];
_.assign(this, _.pick(data, keys));
};
});
return angular.module('content.images', [
])
.constant("IMG_TYPE", {
"ICON": 1,
})
.factory('ImageClassicFn', ImageClassicFn)
.factory('ImageUnableToExtendFn', ImageUnableToExtendFn)
.service('ImageService', ImageService);
});