前端把含有对象的新数组往含有对象老数组里面push，重复的值不要

可以使用forEach方法遍历新数组，然后使用findIndex方法查找老数组中是否已经存在该对象，如果不存在则使用push方法将其添加到老数组中。

代码示例：

let oldArray = [{id: 1, name: 'apple'}, {id: 2, name: 'banana'}, {id: 3, name: 'orange'}];
let newArray = [{id: 2, name: 'banana'}, {id: 4, name: 'grape'}, {id: 5, name: 'watermelon'}];

newArray.forEach(item => {
  let index = oldArray.findIndex(oldItem => oldItem.id === item.id);
  if (index === -1) {
    oldArray.push(item);
  }
});

console.log(oldArray); // [{id: 1, name: 'apple'}, {id: 2, name: 'banana'}, {id: 3, name: 'orange'}, {id: 4, name: 'grape'}, {id: 5, name: 'watermelon'}]