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对象数组Javascript中的增量ID

javascript

MrX · 技术社区 · 4 年前

我有一个数组对象和一个数组,如下所示:

let data = [{"name": "Apple"} , {"name": "Orange"}, {"name": "Pineapple"}]
let selected = [];

我实现了点击进入 data 数据 selected . 在其ID为的索引中,没有 挑选出来的

  const dataObject = {"name": "Apple"};
  dataObject['position'] = selected.length;
  selected.push(dataObject);

  const dataObject = {"name": "Apple"};
  selected.push(dataObject);
  for(let i = 0; i<selected.length; i++) {
    selected[i]['position'] = i;
  }

奇怪的是如果有相同的物体 Apple, Orange, Apple ,我在数组中得到了错误的ID,比如:

[{"name": "Apple", position: 2} , {"name": "Orange", position: 1}, {"name": "Apple", position: 2}]

#编辑:

这里是可复制代码:

let data = [{"name": "Apple"} , {"name": "Orange"}, {"name": "Pineapple"}]
let selected = [];

const dataObject = {"name": "Apple"};
selected.push(dataObject);
selected.push(dataObject);
for(let i = 0; i<selected.length; i++) {
  selected[i]['position'] = i;
}

document.write('<br>' + JSON.stringify(selected));

// Output : [{"name":"Apple","position":1},{"name":"Apple","position":1}] 
// Output Expect: [{"name":"Apple","position":0},{"name":"Apple","position":1}]

我不知道是什么错,任何建议都会对我有帮助。提前感谢

1 回复 | 直到 4 年前

kewlashu 4 年前

dataObject 在中通过引用分配 selected 数组,所以它的同一个对象被你分配两次,一次改变将改变 挑选出来的 数组,因为它们是同一个对象。

let data = [{"name": "Apple"} , {"name": "Orange"}, {"name": "Pineapple"}]
let selected = [];

const dataObject = {"name": "Apple"};

//assigning a new object to selected by using dataObject
selected.push({"name":dataObject.name});

//assigning a new object to selected by using dataObject
selected.push({"name":dataObject.name});

for(let i = 0; i<selected.length; i++) {
  selected[i]['position'] = i;
}

document.write('<br>' + JSON.stringify(selected));

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