// これまでの関数
var printName = function() {
    document.write(this + "<br>");
    document.write(this.myName + "<br>");
};
var human = {
    myName: "yuu",
    print: printName
}
human.print();
 
// アロー関数
var printNameArrow = () => {
    document.write(this + "<br>");
    document.write(this.myName + "<br>");
};
var humanArrow = {
    myName: "mamoru",
    print: printNameArrow
}
humanArrow.print();