JS Advance

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Advance JS

構造函數constructor Function

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function createCard(initName){
this.name=initName

}

const a1 = new createCard("Ma")
const a2 = new createCard("Ma2")
const a3 = new createCard("Ma3")
const a4 = new createCard("Ma4")
const a5 = new createCard("Ma5")
console.log(a1)
console.log(a2)
console.log(a3)

output

createCard { name: ‘Ma’ }
createCard { name: ‘Ma2’ }
createCard { name: ‘Ma3’ }

array function =>

In ES6 there is a new function called array function, which you can write shorter function.

Before ES6

function hello(){}

after ES6

let hello = function (){}
shorthand
let hello = () =>{}

function without passing paramter

Before ES6 (normal function)

ex: function hello(){}

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function test(a ,b){
console.log(a, b)
}
test('hello', 'world');

ES6 arrow function:

ex: let hello = () =>{}

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const test =(a,b) => {console.log(a, b)}
test('hello', 'world');

function with passing varable and return

Before ES6 (normal function)

ex:

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function arrowSum (a , b)  {
    return a+b
  }
console.log(arrowSum(5,6))

ES6 arrow function:

example
function=()=>{return } //with return
function=()=> // Single line arrow function

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arrowSum=(a,b)=>{
return a+b
}
// or arrowSum=(a, b) =>a+b
console.log(arrowSum(5,6))

We can either add return or not. Without return we call it implicit return; values are returned without having to use the return keyword.

reference