js101-with-p-peck

index.js

console.log("hello world !")
var x = 2;

function test(){
    x = 3   
}

// function sum(a ,b){
//     return a +b;
// }

const sum = (a,b) => a + b

function main(){
     x = 1;
     console.log('sum ::' ,sum(1,2));
    // variable 
    // string , number (float , double) , boolean
    
    console.log('x : ',x)

    const a = 1;
    const PI = 3.14;

    let b = true
    b = false
    console.log('b : ',b)

    // flow-control
    let score = 100;
    if(score > 90){
        score = "A"
    } else if(score > 80) {
        score = "B"
    }else {
        score = "C"
    }
    console.log('score :' , score)


    let score2 = score > 90 ? "A" : score > 80 ? "B" : "C"
    console.log('score2 :' , score)
    let _a = 1;
    let _b = 2;
    let _c = 3;
    console.log('debug : ',_a , _b , _c)

    const name = ""
    switch (name) {
        case 'dream':{
            console.log('hello', name)
            break;
        }
        default:
            console.log('hello guest')
            break;
    }


    // Loop // tuple
    const arr = [1,2,3,4,5,6]
    arr.push(7)
    arr.push(8)
    // const test = arr.pop()
    console.log('test : ', "arr[0]", arr[0], " arr[last] :", arr[arr.length - 1])

    // for (let index = 0; index < arr.length; index++) {
        // console.log('index :' , index , " value", arr[index])   
    // }

    // const newArr = []
    // for (let index = 0; index < arr.length; index++) {
    //     if(arr[index] != 2){
    //         newArr.push(arr[index])
    //     }
    // }
    // console.log('newArr :: ',newArr)

    // const newArr = []
    // arr.forEach( (val, index) =>  {
    //     console.log('index :' ,index ,'val :: ',val)
    //     if(val !== 2){
    //         newArr.push(val)
    //     }
    // })
    // console.log('newArr :: ',newArr)

    // const newArr = arr.filter((val) => {
    //     if(val !== 2){
    //         return val
    //     }
    // })
    // console.log('arr :: ',arr)
    // console.log('newArr : ',newArr)

    // Filter  input -> f() -> output
    // Map  f(x) ->  input -> f() -> output
    const pow2 = (value) => value * value
        
    const newPow2 = arr.map(pow2).map(pow2).filter( value => {
        if(value > 1000 ){
            return value
        }
    })
    console.log('newPow2 : ',newPow2)

    // Reduce
    const numbers = [1,2,3,4,5]
    const result = numbers.reduce( (acc, value) => {
        acc = acc + value
        return acc
    }, 0)
    console.log('result : ',result)

    // Find
    const numbers2 = [5,1,2,3,4,5]
    const target5 = numbers2.find(val => val == 5)
    console.log("🚀 target5", target5)


    const a1 = "2";
    if(a1 !== 2){
        console.log('pass')
    }


    

    

}

main();