js 对象合并

Object.assign(obj1,obj2)

obj1为主对象，obj2为被合并对象

合并完成之后重复的键值对将被删除

const target = { a: 1, b: 2 };
const source = { b: 4, c: 5 };

const returnedTarget = Object.assign(target, source);

console.log(target);
// expected output: Object { a: 1, b: 4, c: 5 }

console.log(returnedTarget);
// expected output: Object { a: 1, b: 4, c: 5 }