jsのアロー関数と通常の関数の違い

let x = function function_name(parameters){ 
   // 函数体
};

let square = function(x){ 
  return (x*x); 
}; 
console.log(sqaure(9));

let x = (parameters) => { 
    // 函数体
};

var square = (x) => { 
    return (x*x); 
}; 
console.log(square(9));

let user = { 
    name: "GFG", 
    gfg1:() => { 
        console.log("hello " + this.name); 
    }, 
    gfg2(){        
        console.log("Welcome to " + this.name); 
    }   
 }; 
user.gfg1(); 
user.gfg2();

let user = {       
    show(){ 
        console.log(arguments); 
    } 
}; 
user.show(1, 2, 3);

let user = {      
        show_ar : () => { 
        console.log(...arguments); 
    } 
}; 
user.show_ar(1, 2, 3);

let x = function(){ 
    console.log(arguments); 
}; 
new x =(1,2,3);

let x = ()=> { 
    console.log(arguments); 
}; 
new x(1,2,3);