浅谈Obejct.assign

var ab={
   name:"没有被覆盖",
   age:18
}

var ac = {
  name:"覆盖",
  age:24
}

Object.assign(ab,ac) //如果后面的ac跟ab属于相同，它会覆盖掉前面的ab属性

console.log(ab)    //Object {name: "覆盖", age: 24}

var ab={
   name:"没有被覆盖",
   age:18
}

var ac = {
  name:"覆盖",
  age:24,
  mel:"5489"
}

var ad= Object.assign({},ab,ac) //这里的{}是拷贝目标，后面的ab,ac是拷贝源，拷贝后会返回给ad

console.log(ab) //Object {   name:"没有被覆盖", age:18}
console.log(ad) //Object {name: "覆盖", age: 24, mel: "5489"}