This repository was built to experiment with fundamentals of JavaScript and understanding the nuances of the language. This work was inspired by JavaBrains.io's, 'JavaScript for Developers' course :)
JavaScript (JS)
- Scripting language (Set of commands put up on a script file and is built for a run-time environment - Browser)
- Interpreted. Not compiled.
- Object-Based (Modelled around objects)
- First-Class Functions (Functional Prog.)
- Runs on Browser (Run-Time Environment)
- Lightweight (Low memory footprint, Easy to implement)
- Originally designed and named as ‘LiveScript’ for browsers. But, due to the popularity of Java, they named it, ‘JavaScript’
- Unlike Java (which was used only by professional developers), JavaScript was designed for facilitating the ease of use
- Also, JavaScript is a forgiving language.
- i.e., in case of Java, if there is a mistake, the compiler doesn’t even generate the byte code.
- Whereas, in JavaScript, the interpreter tries to assume what the developer would have written. The program doesn’t break.
- Certain assumptions that the interpreter makes can be surprising and confusing (to be discussed later)
Static vs. Dynamic Web Pages:
HTML —> [Browser] —> Static DOM Tree
Basically, the HTML is provided as an input ‘Document’ to the run-time environment (Browser). This browser reads the document and once it comes across different tags like 'html', 'body', etc., it creates objects for each and everyone of them. So, a 'div' tag and a 'p' tag creates two different objects with the 'div' object being the parent and 'p' object being the child causing the end result is a tree of objects. Hence, called as “DOM” tree
HTML + JavaScript —> [Browser] —> Dynamic DOM Tree
JavaScript has the capability to modify the DOM tree based on the commands that were interpreted and executed on the run-time environment (browser)
Applications:
- Client-Side Development
- Native JS
- jQuery (Framework)
- Angular, React, Ember (Advanced client-side development Frameworks)
- Server-Side Development (More recent advancement)
- NodeJS
- Express
- Browser Extensions (Add-Ons)
- Desktop Applications (Not restricted to browsers)
- Mobile Applications
- IoT (Not so mature)
Development Environment:
- No real need of an explicit IDE. The browser is pretty much what the developers need. Two ways to do it:
- Browser -> Developer Tools -> Toggle Control -> Console [OR]
- Only one command is executed at a time
- Browser -> Developer Tools -> ScratchPad
- Multiple commands (a bunch of code) is executed at a time
Concepts Discussed:
- Variable Declaration
- Primitive Data Types
- Number
- String
- Boolean
- Loose Typing