Javascript on The VikiD Truth

Prototypal Inheritance

Tue, 11 Apr 2023 03:13:18 +0400

Prototypal Inheritance

Here is the truth that makes JavaScript’s object model click: there are no classes in the engine – only objects linked to other objects. The class keyword is tidy syntax over a much older idea called prototypal inheritance.

What it is, in plain words

Every JavaScript object has an internal link to another object, its prototype. When you ask for a property and it isn’t on the object itself, the engine looks at the prototype, then that object’s prototype, and so on until it hits null. That chain is how inheritance works.

Three.js

Sun, 02 Apr 2023 01:54:13 +0400

Three.js | 3DE Code Editor | Making Shapes

Three.js

Making Shapes

Getting Started

Three.js Official Docs Installation

======================================================================================================
Install
======================================================================================================
npm install --save three

npm install --save-dev vite

npx vite

http://localhost:5173

vitejs, using npm, threejs server video, Package management basics

Files, Code

======================================================================================================
index.html
======================================================================================================
<!DOCTYPE html>
<html>
	<head lang="en">
		<meta charset="utf-8">
		<title>My first three.js app</title>
		<style>
			body { margin: 0; }
		</style>
	</head>
	<body>
		<script type="module" src="/main.js"></script>
	</body>
</html>

======================================================================================================
main.js
======================================================================================================

import * as THREE from 'three';

const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 0.1, 1000 );

const renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );

const geometry = new THREE.BoxGeometry( 1, 1, 1 );
const material = new THREE.MeshBasicMaterial( { color: 0x00ff00 } );
const cube = new THREE.Mesh( geometry, material );
scene.add( cube );

camera.position.z = 5;
function animate() {
	requestAnimationFrame( animate );

	cube.rotation.x += 0.01;
	cube.rotation.y += 0.01;

	renderer.render( scene, camera );
}
animate();

to be continued…

Javascript Events

Sun, 02 Apr 2023 01:28:15 +0400

Javascript Events

Here is the truth about events: your JavaScript mostly doesn’t run – it waits. It registers “when this happens, do that”, goes quiet, and the browser (or Node.js) wakes it up when something happens. Learning events is learning to write code that waits well.

What it is, in plain words

An event is a signal that something happened: a click, a key press, a page finishing loading, a network message arriving, a file being read. An event listener (or handler) is a function you attach to a target that will be called when that event fires.

Javascript Functions

Sun, 02 Apr 2023 01:28:00 +0400

Javascript Functions

The truth at the heart of JavaScript: functions are values. You can store them in variables, pass them to other functions, return them, and stick them in objects. Everything clever in the language – callbacks, promises, event handlers, array methods – follows from that one fact.

Javascript Objects

Sun, 02 Apr 2023 01:27:38 +0400

Javascript Objects

Strip away the syntax and here is the truth: a JavaScript object is just a bag of named slots, plus a hidden link to another bag to ask when a slot is missing. Arrays, functions, dates, DOM nodes – all of them are that, underneath.

What it is, in plain words

An object is a collection of properties. Each property has a key (a string or a symbol) and a value (anything – a number, another object, a function). When a property’s value is a function, we call it a method.

Javascript Scope

Sun, 02 Apr 2023 01:27:07 +0400

Javascript Scope

The truth behind scope is simple: every name lives somewhere, and code can only see the names in its own room and the rooms that contain it. That nesting of rooms, decided by where you write the code, is all scope is.

What it is, in plain words

Scope is the region of a program where a name is visible. An environment (the spec calls it an Environment Record) is the actual table, at run time, that maps names to values for that region. Each environment keeps a pointer to its outer environment, forming a chain. When you use a name, JavaScript looks in the current environment, then the outer one, then the next, until it hits the global environment. If the name isn’t there, you get a ReferenceError.

Javascript Variables

Sun, 02 Apr 2023 01:26:09 +0400

Javascript Variables

Here is the truth nobody tells beginners: a variable is not a box that holds a value. It is a name that points at a value. Once that sinks in, half the “weird” behaviour of JavaScript stops being weird.

What it is, in plain words

A variable is a label you attach to a value so you can find it again. In modern JavaScript (everything since ES2015, and everything you should be writing in 2026) you create one with one of two keywords:

Javascript Control Flow

Wed, 24 Aug 2022 01:03:54 +0400

Javascript Control Flow

Equality

Triple Equals
```
 1 === 1;
```
type
value
Double Equals
```
 1 == 1;
```
Weird Examples

 0 == "0" // true
 0 == "" // true
 0 == [] // true

 0 == null // false
 0 == undefined // false

 "true" == true // false
 "false" == false // false

```
 5 == "5";
```
```
 5 === Number("5");
```
Truthy or Falsy?

 "" // falsy
 [] // truthy
 () // truthy
 NaN // falsy
 Infinity // falsy
 0 // falsy

 "" == false // true
 0 == false // true
 0n == false // true
 Nan == false // false
 null == false // false
 undefined == false // false

memorize the 7 falsy values
- ""
  - 0
  - 0n
  - NaN
  - undefined
  - null
  - false

null == null // true
null == false // false
null == true // false

Objects

Javascript Data Types

Wed, 24 Aug 2022 00:05:54 +0400

Javascript Data Types

There are 8 fundamental data types:

Numbers, Strings, Booleans, Objects, Functions, Undefined, Bigints, Symbols

Variables don’t have types. The values have types. remember to use typeof operator.

Numbers

5 0b101 0o5 0x5 5e7

1. ```
10 * "string" => NaN
10/0 => Infinity
-10/0 => -Infinity

Strings
`"" ’’ ```

let s = “Jane is good” s.length //12 s.toLowerCase() s.toUpperCase()

Node Js

Sun, 11 Dec 2016 00:02:18 +0400

Node Js

Official Node Documentation On older Ubuntu releases the command was nodejs, not node:

ln -s /usr/bin/nodejs /usr/bin/node

Mixu’s Node Book

Install NVM Manjaro Linux

Use Node Version Manager, NVM.

sudo pacman -S nvm

nvm install --lts
npm install "package name"
nvm uninstall --lts

Getting Started npm

npm install <package-name>

flags:

Javascript on The VikiD Truth

Prototypal Inheritance

Prototypal Inheritance

What it is, in plain words

Three.js

Three.js

Getting Started

Javascript Events

Javascript Events

What it is, in plain words

Javascript Functions

Javascript Functions

Javascript Objects

Javascript Objects

What it is, in plain words

Javascript Scope

Javascript Scope

What it is, in plain words

Javascript Variables

Javascript Variables

What it is, in plain words

Javascript Control Flow

Javascript Control Flow

Equality

memorize the 7 falsy values

Javascript Data Types

Javascript Data Types

Numbers

Node Js

Node Js

Install NVM Manjaro Linux

Getting Started npm