nested-loops.js

// nested loops and multi-dimensional objects
// We can use nested loops to access all the elements
// inside multi-dimensional arrays or objects

let twoD = [[1, 2, 3, 4, 5, 6, 7],
           [8, 10, 5, 7, 3, 22, 6, 42],
           [123, 54, 12, 11, 9, 15]];

let bigHero = {characters:[
                {name:'Hiro', voice:'Ryan Potter'},
                {name:'Baymax', voice:'Scott Adsit', prop:12},
                {name:'Go Go Tamago', voice:'Jamie Chung'},
                {name:'Fred', voice:'T.J. Miller'}
            ]};

let chars = bigHero['characters'];  //bigHero.characters
for(let i=0, len=chars.length; i<len; i++){
//    console.log(chars[i]);
//    console.log(chars[i].name);
//    console.log(chars[i]['voice']);
    for(let prop in chars[i]){
        console.log(prop, chars[i].prop, chars[i][prop]);
    }
}

//nested for loops
//let rows = twoD.length;
//for(let i=0; i<rows; i++){
//    let items = twoD[i].length;
//    console.log(i, items)
//    for(let n=0; n<items; n++){
//        console.log( twoD[i][n] );
//    }
//}

You are great!