Namespaces in JavaScript

Namespaces are used to help organize code into logical groups. An example of a namespace is MyCo.ERP.Customers, which may contain code regarding ERP Customers. I could also have a namespace called MyCo.CRM.Customers. When writing an app, I can reference each piece of code using their fully qualified name to avoid confusion of what methods I would like to run. In languages like C#, namespaces are easily implemented. In JavaScript, we can … Continue reading Namespaces in JavaScript

JavaScript === (Triple Equals)

The triple equals sign in JavaScript means “equality without type coersion”. That means, the type and values must both be equal. Take for example the scenario where 0 is false. If we compare with 2 equal signs, the following statement is true. This is because the equality operator converts if they are not of the same type: 0 == false // true If we compare the same 0 and false … Continue reading JavaScript === (Triple Equals)

JavaScript Error Handling

JavaScript contains different ways to handle errors. One way is using try/catch/finally. In the example below, variable y does not exist. try { var x = 1 + y; console.log(t); } catch(e) { console.log(“Error: ” + e); } finally { console.log(“Run finally”); } Running this produces: Note you can also use name, message and stack to get error information: try { var x = 1 + y; console.log(t); } catch(e) … Continue reading JavaScript Error Handling

Debugging TypeScript with Google Chrome and Node

To debug TypeScript using Visual Studio Code, install the Debugger for Chrome, located at: https://marketplace.visualstudio.com/items?itemName=msjsdiag.debugger-for-chrome: You will see the message: The debugger will now be installed: Let’s say in our environment we have: A folder called TS with TypeScript files A TS file called HelloWorld.ts Like below: And we have an index.html page which calls the HelloWorld.ts file: Now, update your tsconfig.json file like below: And the launch.json file: Now, if … Continue reading Debugging TypeScript with Google Chrome and Node

Installing TypeScript for Visual Studio Code

Visual Studio Code has support for the TypeScript language. To use it, create a new file with TypeScript code in Visual Studio Code: And save the file, we will see TypeScript as an option: We can see Visual Studio Code has TypeScript Intellisense: Visual Studio Code does not include the TypeScript Compiler (tsc). To install it using the Visual Studio Code terminal, type: npm install -g typescript You will see … Continue reading Installing TypeScript for Visual Studio Code

Installing TypeScript on Node

To install TypeScript on Node, run the command: npm install -g typescript Now let’s create a new TypeScript file. First create a directory for our TypeScript project called TS, and create a new file HelloWorld.ts: Run the TypeScript compiler command: tsc HelloWorld.ts This will create a new js file: With JavaScript code:  

Introduction to TypeScript

TypeScript is a superset of JavaScript developed by Microsoft that supports classes, modules and interfaces, along with several other features. It is a static type language, meaning it will validate code at development time. JavaScipt is a dynamic language, which does not validate code at development time. Having a static type language is very useful for building robust code. To try out TypeScript online, go to www.typescriptlang.org and select Playground: You will … Continue reading Introduction to TypeScript

JavaScript – Calling Functions

Let’s go through an example of different ways to call a function in JavaScript. Let’s say we have a function that prints Hello World to the console. We can call this as: function HelloWorld() { console.log(“Hello World”); } HelloWorld(); This function can also be assigned an anonymous variable and called as below: var i = function() { console.log(“Hello World”); } i(); Or also run immediately as: var i = function() … Continue reading JavaScript – Calling Functions

JavaScript – Use Strict

“use strict” is a feature of JavaScript that tells the compiler to use a strict context. For example, consider the code below. This code produces no errors, and displays “1” in the console: However, let’s say we didn’t include “var” before our variable. In normal JavaScript without using “use strict”, this would be fine. However, with “use strict”, it throws an error: For more information: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode  

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