javascript - JavaScript `delete`运算符无法正常工作

我有一个类似下面的对象:

var doc = {
  local: {
    username: 'admin',
    status: true,
    password: '$2a$08$81Kq7/59ZASHl5k9n5cNvOUSl/HYgpLKZjs66P/OJV8vw.nHW60Ta',
    lastname: 'admin',
    firstname: 'admin',
    email: '[email protected]',
    datetime_modified: 'TueAug30201623: 10: 56GMT+0530(IST)',
    datetime_created: 'MonAug29201622: 34: 12GMT+0530(IST)'
  },
  roles: [
    'ADMIN',
    'HR'
  ],
  GridOrder: [
    {
      _id: '57e507fce94094be085425c9',
      domainName: 'items'
    }
  ],
  _id: '57c46b0c12907af910167ff5',
  __v: 9
}

现在，我想从“doc”中删除属性“GridOrder”。
我尝试使用“删除”，如下所示:

delete doc.GridOrder

也像下面这样:

delete doc['GridOrder']

但是什么也没发生。我也没有任何错误。

如何从“文档”中删除“GridOrder”。有任何想法吗？

最佳答案

使对象属性可配置

使用上述代码时，您的最小示例将按预期工作。

根据您的评论，GridOrder实际上是使用Object.defineProperty()定义的，默认情况下，它会创建不可配置(读取:不可删除)属性。

定义属性configurable: true时，只需将Object.defineProperty传递给GridOrder即可。

var doc = {
  local: {
    username: 'admin',
    status: true,
    password: '$2a$08$81Kq7/59ZASHl5k9n5cNvOUSl/HYgpLKZjs66P/OJV8vw.nHW60Ta',
    lastname: 'admin',
    firstname: 'admin',
    email: '[email protected]',
    datetime_modified: 'TueAug30201623: 10: 56GMT+0530(IST)',
    datetime_created: 'MonAug29201622: 34: 12GMT+0530(IST)'
  },
  roles: [
    'ADMIN',
    'HR'
  ],
  _id: '57c46b0c12907af910167ff5',
  __v: 9
}

// Objects defined this way cannot be deleted unless `configurable` is set to `true`
Object.defineProperty(
  doc,
  'GridOrder',
  {
    configurable: true, // Defaults to `false`
    value: [
      {
        _id: '57e507fce94094be085425c9',
        domainName: 'items'
      }
    ]
  }
);

console.log('doc.GridOrder: ', doc.GridOrder);
console.log('delete doc.GridOrder: ', delete doc.GridOrder);
console.log('doc.GridOrder: ', doc.GridOrder);

警告



Advanced objects in JavaScript

如果您无权使用defineProperty创建GridOrder的脚本，则以后将无法对其进行修改或删除。

例如，这将失败:

/*
 * Imagine this is provided by some third-party library that you're unable to edit
 */

var doc = {};

// Objects defined this way cannot be modified or deleted because `configurable` defaults to `false`.
Object.defineProperty(
  doc,
  'GridOrder',
  {
    value: [
      {
        _id: '57e507fce94094be085425c9',
        domainName: 'items'
      }
    ]
  }
);

/*
 * Within your script…
 */

console.log('doc.GridOrder: ', doc.GridOrder);
console.log('delete doc.GridOrder: ', delete doc.GridOrder);
console.log('doc.GridOrder: ', doc.GridOrder);

// …attempts to redefine non-configurable properties will fail
Object.defineProperty(
  doc,
  'GridOrder',
  {
    configurable: true
  }
);

console.log('This will never be seen because an Error has been thrown above.');