React.js

React.js is a JavaScript library created and maintained by Facebook for building user interfaces.  React maintains a virtual “DOM” in memory and makes updates to the real DOM only as needed.

React Native applies the same principles to cross-platform UI development for iOS and Android.

React.js components are typically written in JSX, a JavaScript extension syntax that allows inlining HTML with code, among other features.  JSX is optional and not required to use React.

Thoughts?  I really like how UI elements and state are componentized and non-global.  I don’t like how there are now two DOMs – the real one and the React-managed one.

The React tutorial is a Tic Tac Toe game; here’s my completed version.

JavaScript Array.map() and arrow functions

In newer versions of JavaScript (ECMAScript 5 +) we have the wonderful Array.map() method, and in even newer versions (ECMAScript 6+ aka ECMAScript 2015) we have the new arrow function expressions.

This allows for concise and powerful code like the following:

// an Array of integers
var array1 = [1, 4, 9, 16];

// create a new Array from the original Array using a function
const map1 = array1.map(x => x * 2);

// display; expected output: Array [2, 8, 18, 32]
console.log(map1);

NoSQL and DynamoDB

Today I will look at the NoSQL concept and specifically Amazon’s DynamoDB.

NoSQL stands for “No SQL”, which means you don’t use SQL (Structured Query Language) to manage the database.  Data is not arranged into relational tables (with relational indices that point to other tables), but is arranged in a variety of data models, including document, graph, key-value, and columnar.

NoSQL was born because of the need for scalability and performance.  In the early 2000s it was discovered that relational databases do not scale well at a reasonable cost.

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