Typescript

TypeScript is a strongly typed programming language that builds on JavaScript.

~ Typescrpt Docs

Documentation on JavaScript at the Mozilla Web Docs.

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Strongly typed vs Loosely typed

The terms strongly typed and loosely typed refer to how programming languages handle types, particularly how strict they are about type conversions and type safety.

Strongly typed languages	Loosely typed languages
1. Examples - Java, C++, C, Rust 2. Benefits - 1. Lesser runtime errors 2. Stricter codebase 3. Easy to catch errors at compile time	1. Examples - Python, Javascript, Perl, php 2. Benefits 1. Easy to write code 2. Fast to bootstrap 3. Low learning curve

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Does not work

#include <iostream>
int main() {
int number = 10;
number = "ten";
return 0;
}

Does work

function main() {
  let number = 10;
  number = "text";
  return number;
}

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What is typescript?

TypeScript is a programming language developed and maintained by Microsoft.

It is a strict syntactical superset of JavaScript and adds optional static typing to the language.

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Where/How does typescript code run?

Typescript code never runs in your browser. Your browser can only understand javascript.

1. Javascript is the runtime language (the thing that actually runs in your browser/nodejs runtime)

2. Typescript is something that compiles down to javascript

3. When typescript is compiled down to javascript, you get type checking (similar to C++). If there is an error, the conversion to Javascript fails.

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Typescript compiler

tsc is the official typescript compiler that you can use to convert Typescript code into Javascript

There are many other famous compilers/transpilers for converting Typescript to Javascript. Some famous ones are -

1. esbuild

2. swc

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How to create a ts project

Step 1 - Install typescript globally

npm install -g typescript

Step 2 - Initialize an empty Node.js project

mkdir node-app
cd node-app
npm init -y

Step 3 - Initialize a tsconfig.json file.

npx tsc --init

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