Typescript

Day-1

1. What is Typescript?

• Typescript is the superset of Javascript
• It compiles into regular Javascript, so it runs anywhere Javascript does
• File ends with .ts

2. How Typescript works?

• You write code in Typescript
• Typescript compiler convers it into Javascript
• Javascript runs in browser, Node.js or any JS environment

3. Why Typescript ?

• Helps catch mistakes early
• Makes large projects easier to manage
• Type Saftey

4. Setup

• Node.js
• Typescript Complier
  • Run it on root as admin npm install -g typescript to install
  • tsc fileName.ts > Compiles and creates the JS file
  • node fileName.js > Run the JS file
• Any IDE
• Typescript executor
  • Run it on root as admin npm install -g tsx to install
  • tsx fileName.ts > Runs the ts file without creating the js file

Day-2

Comments

• Signle Line (//sample code) > cmd + /
• Multi Line (/_ sample story _/) > shift+alt(option)+a

Variables

• Container which holds the Value/data
• var, let and const
• syntax > ex:let age:number = 30
• Scope
  • Functional
  • Block

Keyword	Scope	Redeclaration	Reassignment	Hoisting	Usage Recommendation
var	Function	Yes	Yes	Yes	Avoid in modern code
let	Block	No	Yes	No	Use if value changes
const	Block	No	No	No	Use by default

Day-3

• Javascript is the Dynamically typed language
• Typescript is the Statically typed language

Data Types

1. Premitive Datatypes
   • Can store only one single value a. Number b. String c. Boolean d. Null e. undefined f. Any g. Union h. Void
2. Non-Premitive Datatypes

• Can store group of Objects a. Array b. Class c. Function d. Interface, etc..

let age:number = 32

1. Type/Data Type
2. Annotations
3. Type Inference

Day-4

Operators

• Arithmetic
• Assignment
• Relational
• Logical
• Increment/Decrement
• Conditional(Ternary)

Day-5

Statements

• Conditional Statements
  • if
  • if...else
  • if...else if...else
  • switch

Day-6

Loops

• While

console.log("1 to 10");
let count = 1;

while (count < 11) {
  console.log("Count is: " + count);
  count++;
}

• Do-while

console.log("5 to 1");
let j = 5;
do {
  console.log(j);
  j--;
} while (j >= 1);

• For Loop

console.log("1 to 10");

for (let i = 1; i <= 10; i++) {
  console.log(i);
}

• Break and Continue

console.log("1 to 10 but skip 5");
for (let i = 1; i <= 10; i++) {
  if (i === 5) {
    continue;
  }
  console.log(i);
}

console.log("1 to 10 but stop at 5");
for (let i = 1; i <= 10; i++) {
  if (i === 5) {
    break;
  }
  console.log(i);
}

Day-7

Functions

• Named Function
  • Arrow/Lambda function
  • Default Parameters
  • Optional Parameters
  • Rest Parameter

function addGivenNumbers(...num: number[]): void {
  let i = 0;
  let sum: number = 0;
  for (let i = 0; i < num.length; i++) {
    sum = sum + num[i];
  }
  console.log(sum);
}
addGivenNumbers(1, 3, 43, 24, 56, 7, 8, 76, 2);