Skip to main content

Posts

Type or Category or Classification of Design Patterns

 Type or Category or Classification of Design Patterns Creational   Based on the concept of creating an object.     Class       Factory Method This makes an instance of several derived classes based on interfaced data or events.     Object       Abstract Factory Creates an instance of several families of classes without detailing concrete classes.       Builder Separates object construction from its representation, always creates the same type of object.       Prototype A fully initialized instance used for copying or cloning.       Singleton A class with only a single instance with global access points.                    Structural   Based on the idea of building blocks of objects.     Class   ...

Difference between webstorage, cookie, local storage & session storage

WebStorage The Window object implements the WindowLocalStorage and WindowSessionStorage objects which has localStorage(window.localStorage) and sessionStorage(window.sessionStorage) properties respectively. These properties create an instance of the Storage object, through which data items can be set, retrieved and removed for a specific domain and storage type (session or local). For example, you can read and write on local storage objects as below localStorage.setItem('logo', document.getElementById('logo').value); localStorage.getItem('logo'); What are the differences between cookie, local storage and session storage Below are some of the differences between cookie, local storage and session storage, Feature Cookie Local storage Session storage Accessed on client or server side Both server-side & client-side client-side only client-side only Lifetime As configured using Expires option until deleted until tab is closed SSL support Supported Not supported N...

Cloud Computing basics

SaaS - Software as a Service is on-demand access to ready-to-use, cloud-hosted application software. E.g. Google Docs, Google Form, Google Spreadsheet.  PaaS - Platform as a Service is on-demand access to a complete, ready-to-use, cloud-hosted platform for developing, running, maintaining, and managing applications. E.g. Amazon EC2 T2 Micro instances 1 GB memory & 1 vCPU under free tier, Microsoft Azure IaaS - Infrastructure as a Service The service provides all of the infrastructures to the business. It provides on-demand access to cloud-hosted physical and virtual servers, storage, and networking - the backend IT infrastructure for running applications and workloads in the cloud. E.g. host.com that provides dedicated servers to organizations. VMware offers support for IaaS for carving out a system rack, network storage & computer into an isolated system for customers. StaaS - Storage as a Service E.g. Carbonite, Amazon S3 Storage as a service (STaaS) is a data storage bus...

Top Competitive exams in India for students & professionals

I have compiled this list of some of the most prominent competitive entrance examinations for the benefit of students. (Source: Wikipedia & the internet)   1. GRE The Graduate Record Examinations (GRE) is a standardized test that is an admissions requirement for many graduate schools in the United States and Canada and few in other countries. The GRE is owned and administered by Educational Testing Service (ETS) MBA GRE score can be used for MBA programs in some schools. The GMAT (Graduate Management Admission Test) is a computer-adaptive standardized test in mathematics and the English language for measuring aptitude to succeed academically in graduate business studies. Business schools commonly use the test as one of many selection criteria for admission into an MBA program. Starting in 2009, many business schools began accepting the GRE in lieu of a GMAT score. Policies varied widely for several years. However, as of the 2014–2015 admissions season, most business schools acc...

Cannot call a javascript function from HTML file in codesandbox.io. ??!!!

I was a bit surprised to see that you cannot reference a javascript function using a Vanilla sandbox using codesandbox.io site. Upon googling a bit here is what I found:   https://github.com/codesandbox/codesandbox-client/issues/1502   Here is the working sandbox where we can call a javascript function from an HTML file. https://codesandbox.io/s/sleepy-sunset-w0wds?file=/src/index.js Here is the explanation provided by the codesandbox.io folks on it: k, so the explanation is that in the vanilla template / parcel environment we're doing module bundling, handling src/index.js as a module. Because modules are evaluated in their own (private) scope, if you want to access from html something inside the module, you can put it on the browser's global scope, which is window. Alternatively, you can use the static template / environment, where we don't do any bundling, like https://codesandbox.io/s/quirky-flower-rm20y (but then you lose the ability to require / import).