/Typescript-learning

Primary LanguageJavaScript

Typescript - basics

  • tsc is static type for JS
  • used at compile time

Main Types

  • string , number, boolean
  • arrays, objects, tuples
  • Generic

const genericArray: Array = [10, 20, 30] type syntax is syntax sugar for generic one

const typeArray: number[] = [100,200,300]

Tuples const items:[string, number] = ["krishna", 108] const items:[[Array],string] = ["krishna", 108]

let personTuple: [string, number, boolean] = ["Krishna",10,false];

other imp stuff while working with tsc

  • tsconfig.json (settings for typescript project)

    • build -> compilerOptions
    • src -> includes
    • esversion -> target

  • tslint to enforce good coding practices

some learnings

  • typescript is used in development and not in production
  • transpiles to js while publishing the app

some imp commands npm i tslint-config-airbnb tslint --save-dev

after installing lint to check the lint errors npx tslint --project .

tsc

In TypeScript object types, the comma (,) and semicolon (;) separators between properties are interchangeable. All of these spellings denote the same type:

let objectType : { prop1: string; prop2: number, prop3:boolean; }

let person1: {firstName: string, age: number}; let person1: {firstName: string; age: number}; let person1: {firstName: string; age: number;};

// A variable person with both a type annotation and an initializer let person: { firstName: string; age: number; } = { firstName: "Franz", age: 23, };

Object Types Are Not Exact