es6のアロー機能の利点は何ですか?

// 函数声明
function sayHi(someone) {
  return `Hello, ${someone}!`;
}
// 函数表达式
const sayHi = function(someone) {
  return `Hello, ${someone}`;
}

const sayHi = (someone) => {
  return `Hello, ${someone}!`;
}

删掉一个关键字，加上一个胖箭头；
没有参数加括号，一个参数可选择；
多个参数逗号分隔，

const numbers = [5,6,13,0,1,18,23];
//原函数
const double = numbers.map(function (number) {
    return number * 2;
})
console.log(double);
//输出结果
//[ 10, 12, 26, 0, 2, 36, 46 ]
//箭头函数     去掉function, 添加胖箭头
const double2 = numbers.map((number) => {
    return number * 2;
})
console.log(double2);
//输出结果
//[ 10, 12, 26, 0, 2, 36, 46 ]
//若只有一个参数，小括号能够不写（选择）
const double3 = numbers.map(number => {
    return number * 2;
})
console.log(double3);
//如有多个参数，则括号必须写；若没有参数，（）须要保留
const double4 = numbers.map((number,index) => {
    return `${index}:${number * 2}`;  //模板字符串
})
console.log(double4);

const double3 = numbers.map(number => {
    return number * 2;  
    //return 返回内容;
})

当你想简单返回一些东西的时候，以下：去掉return和大括号，把返回内容移到一行，较为简洁;
const double3 = numbers.map(number => number * 2);

const Jelly = {
    name:'Jelly',
    hobbies:['Coding','Sleeping','Reading'],
    printHobbies:function () {
        this.hobbies.map(function (hobby) {
            console.log(`${this.name} loves ${hobby}`);
        })
    }
}
Jelly.printHobbies();
// undefined loves Coding
// undefined loves Sleeping
// undefined loves Reading

//中心代码
printHobbies:function () {
    var self = this; // 设置变量替换
    this.hobbies.map(function (hobby) {
        console.log(`${self.name} loves ${hobby}`);
    })
}
Jelly.printHobbies();
// Jelly loves Coding
// Jelly loves Sleeping
// Jelly loves Reading
在ES6箭头函数中，咱们这样写code
//中心代码
printHobbies:function () {
   this.hobbies.map((hobby)=>{
       console.log(`${this.name} loves ${hobby}`);
   })
}
// Jelly loves Coding
// Jelly loves Sleeping
// Jelly loves Reading