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typescript

信息

原始 MD by 咏陞

javascript VS typescript​

  • 靜態強型別​

  • javascript的超集​

  • 對於物件導向的支援更好​

  • 語法較為統一​

  • 減少debug所花費的時間​

  • 聰明的錯誤提示​

tsconifg​

yarn init -y
yarn add -D typescript
tsc init     // yarn run tsc init

你或許會需要這個酷東西

yarn add -D ts-node

type

primitives type​

  • string
  • number
  • boolean
  • undefined
  • null
  • symbol
  • void
let num1 = 1;
let num2:number;
num2 = 1;

object type​

  • Array \<T>
  • JSON
  • class instance
  • tuple
  • map
  • enum
let arr1:Array<number> = [1,2,3]
let arr2:number[] = [1,2,3]

let obj={
    attr1:123,
    attr2:'str'
}

let tuple :[number,string,obj]

let map = new Map([
    ["key1",1],
    ["key2",2]
]);

enum msg{
    susseces,
    error
}

特殊型別​

  • any
  • nerver
  • unknow
let shit:any = 'str';
let obj:number;
obj = shit;
console.log(obj);

複合型別​

  • |
  • &

?!

const vs readonly​

constreadonly
目的避免重新賦值避免重新賦值
檢查時間run-time & compile-timecompile-time
目標variableproperty

narrowing & type guard​

  • typeof
  • instanceof
  • in
  • is
  • ...