let in 和 let of

    let arrObj = [{name: 'aaa', age: 11}, {name: 'bbb', age: 22}, {name: 'ccc', age: 33}]

    for(let i in arrObj){

      console.log("i:", i);   // i: 0        i: 1          i: 2

    }

    for(let i of arrObj){

      console.log("i:", i);   // i: {name: 'aaa', age: 11}         i: {name: 'bbb', age: 22}         i: {name: 'ccc', age: 33}

    }