https://github.com/codewith-ark/javascript
Learning JavaScript by coding. The following branch contains codes (in JavaScript language) for each of the programming concept
https://github.com/codewith-ark/javascript
javascript learning-by-doing learning-js
Last synced: 9 months ago
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Learning JavaScript by coding. The following branch contains codes (in JavaScript language) for each of the programming concept
- Host: GitHub
- URL: https://github.com/codewith-ark/javascript
- Owner: Codewith-ARK
- Created: 2023-03-16T04:37:52.000Z (about 3 years ago)
- Default Branch: master
- Last Pushed: 2024-03-25T06:41:49.000Z (about 2 years ago)
- Last Synced: 2025-03-26T02:12:57.495Z (about 1 year ago)
- Topics: javascript, learning-by-doing, learning-js
- Language: JavaScript
- Homepage: https://codewith-ark.github.io/JavaScript/
- Size: 4.71 MB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
Awesome Lists containing this project
README
# Learning JavaScript
- Getting Started
- JS in the Web Browser
- [`console.log()`](#consolelog)
- [Variables](#variables)
- [Data Types](#primitive--non-primitive-data-types)
- [String Concatenation](#string-concatenation)
- [Operators]()
- Conditional Statements
## Console.log()
This is the method used to output text onto the console **(not the screen)**
```js
console.log("Hello World!"); //semi-colons are optional
// you can format the code in Console bu using `%c`
console.log("%c Hi There!", "color:blue; font-size:48px;");
```
---
## Variables
There are (3) keywords to declare variables:
- `var` the most lenient type of Variables.
- `let` included in ES6 somewhat strict type of variables
- `const` used to create constant (unmodifiable variables)
---
## Variables
There are (3) ways to create a variable in JS:
- `var`: creates a somewhat global variable.
- `let`: creates a scoped variable
- `const`: creates a CONSTANT variable
```js
/* Using let */
let _var = 67;
function myFunc() {
// this variables is only accessible inside the function.
let _var = 100;
}
/* Using const */
// this variable can not be 'reassigned'
const _constant = "I am unchangeable";
/* Using var */
// This variable can be accessed EVERYWHERE in the code
var _anotherVar = null;
```
---
## Primitive & Non-Primitive Data Types
**Primitive**: Data types that are built-in to the language. Examples are:
```js
// nn bb ss u
let _null = null;
let _num = 34;
let _bool = true;
let _bigInt = 456n;
let _string = "ARK";
let _symbol = Symbol("I am a Symbol!");
let _undef = undefined;
```
**Non-Primitive**: Data Types that are user-defined. Examples are: Objects.
```js
let _myObj = {
name: "ARK",
age: 19,
skinColor: "Dark Orange",
};
```
In the above code an object is assigned to the variable named '\_myObj'. The object contains `key-value pair` this means every properties of object can be accessed by a specific key. There are several ways to access the properties of an object
### **Using dot (.) operator:**
```js
let name = _myObj.name;
console.log(name);
// output: "ARK"
```
### **Using Object Literal:**
```js
let age = _myObj["age"];
console.log(age);
// Output: 19
```
## String Concatenation
Concatenation is the process used to combine two or more string together. There are severel ways of concatenating String in **JavaScript**
1. using the `concat` method
1. using the `+` operator
1. using the `,` operator
---
**Method 1:**
```js
str1 = "My";
str2 = "String";
// combines the two existing strings
str3 = str1.concat(str2);
// MyString
```
**Method 2:**
```js
str1 = "My name is";
str2 = "ARK";
console.log(str1 + str2);
// My name isARK
```
**Method 3:**
```js
str1 = "My name is";
str2 = "ARK";
console.log(str1, str2);
```
---
## Loops
There are many types of loops in JS:
- `For loop`
```js
for (let i = 0; i < 11; i++) {
console.log(i);
}
```
- `For-in loop:` Used for printing the values of an object
```js
// An object literal assigned to a variable named 'Obj'
let obj = {
name: "ARK",
age: 19,
isMale: true,
};
for (let keys in obj) {
console.log(`${keys}: ${obj[keys]}`);
}
/*
Output:
name: ARK
age: 19
isMale: true
*/
```
- `For-of loop:` used to iterate over the elements of an Array
```js
// Array of fruits (string).
let arr = ["lemon", "banana", "apple", "strawberry"];
for (let item of arr) {
console.log(`${item}`);
}
/*
Output:
lemon
banana
apple
strawberry
*/
```
- `While Loop`
```js
let i = 0;
while (true) {
console.log(++i);
}
// Output: 1, 2, 3...
```
---
## String Methods
```js
let name = "ark";
console.log(name.length); // tells the number of charachters present in the string
console.log(name.toUpperCase()); // converts the string to UPPERCASE
console.log(name.toLowerCase()); // converts the string to lowercase
console.log(name.replace("a", "s")); // replaces 'a' in string 'ark' with 's'. Output: 'srk'
```
---
## Arrays
A data type that is used to store collection of data types.
```js
let arr = ["banana", 70, 3.142, true];
```
## Methods of Array
```js
arr.push("ARK"); // adds new element at the end
arr.pop(); // removes element from the end
arr.shift(); // removes element from the front
arr.unshift(); // adds element from the front
```
### Turnary Operator
Syntax:
```js
condition ? if_true : if_false;
```
Example:
```js
let result = 1 > 2 ? "1 is greater than 2" : "1 is NOT greater than 2";
console.log(result);
```
---