for循環和for in 循環 for of循環的區別

    //for循環和for in 循環 for of循環的區別
    let array = [1, 2, 3, 4, 5];
    array.qqq = 123;
    for(let i = 0; i < array.length; i++){
        console.log(array[i]);//1, 2, 3, 4, 5
    }
    for(let k in array){//通常須要判斷hasOwnProperty
        console.log(array[k]);//1, 2, 3, 4, 5, 123 
    }
    for(let value of array){
        console.log(value);//value是數組中的值  1，2，3，4，5
    }