数组和对象过滤器 javascript

Question

我有以下数组

permissionList: [
        {
            name: "Database",
            permissions: [
                {
                    id: "610c3b02e5e2dc586c6bfbbd",
                    key: "Database/View",
                    name: "View Database",
                    description: "permission for view database module",
                    createdAt: "",
                    updatedAt: "",
                },
                {
                    id: "610c3b02e5e2d3w586c6bfbfs",
                    key: "Database/Add",
                    name: "Add Database",
                    description: "permission for Add database module",
                    createdAt: "",
                    updatedAt: "",
                },
            ],
        },
        {
            name: "Project",
            permissions: [
                {
                    id: "610c3b02e5e2dc586c6bfbbd",
                    key: "Project/View",
                    name: "View Project",
                    description: "permission for view Project module",
                    createdAt: "",
                    updatedAt: "",
                },
                {
                    id: "610c3b02e5e2d3w586c6bfbfs",
                    key: "Project/Add",
                    name: "Add Project",
                    description: "permission for Add Project module",
                    createdAt: "",
                    updatedAt: "",
                },
            ],
        },
    ],

当有人进入数据库/视图时，应该过滤如下。

permissionList: [
        {
            name: "Database",
            permissions: [
                {
                    id: "610c3b02e5e2dc586c6bfbbd",
                    key: "Database/View",
                    name: "View Database",
                    description: "permission for view database module",
                    createdAt: "",
                    updatedAt: "",
                }
            ],
        },
]

Answer 1

您可以使用两个简单的功能进行过滤，一个过滤内部权限列表，第二个如果内部列表不为空，则列出外部权限列表。

// Function to filter inner permissions if their key is equals to the requested key
function innerFilter(permissions, key) {
   return permissions.filter(permission => permission.key == key);
}


// Function to be called with the permission list. It filter inner
// permissions, than it consider only not empty inner permissions
function outerFilter(list, key) {
    return list
      // make a copy of original items with a list of permissions
      // satisfying the requested key
      .map(item => { 
         return {  
            ...item, 
            permissions: innerFilter(item.permissions, key) 
         } 
      })
      // filter the items having at least 1 inner permission
      // satisfying the requested key
      .filter(item => item.permissions.length > 0)
}

并使用 outerFilter 函数调用它

var searchedList = outerFilter(permissions, "Database/View");

请考虑此代码尚未经过测试，因此可能会出现拼写错误，请作为一个想法。如有必要，添加对 null 或未定义值的测试。

最终你可以将这两个函数组合成一个函数，如下所示：

// Function to be called with the permission list. It filter inner
// permissions, than it consider only not empty inner permissions
function filterByPermissionKey(list, key) {
    return list
      // make a copy of original items with a list of permissions
      // satisfying the requested key
      .map(item => { 
         return {  
            ...item, 
            // Extract the sublist of permissions having the requested key
            permissions: item.permissions.filter(permission => permission.key == key)
         } 
      })
      // filter the items having at least 1 inner permission
      // satisfying the requested key
      .filter(item => item.permissions.length > 0)
}

Answer 2

const permissionList = [
        {
            name: "Database",
            permissions: [
                {
                    id: "610c3b02e5e2dc586c6bfbbd",
                    key: "Database/View",
                    name: "View Database",
                    description: "permission for view database module",
                    createdAt: "",
                    updatedAt: "",
                },
                {
                    id: "610c3b02e5e2d3w586c6bfbfs",
                    key: "Database/Add",
                    name: "Add Database",
                    description: "permission for Add database module",
                    createdAt: "",
                    updatedAt: "",
                },
            ],
        },
        {
            name: "Project",
            permissions: [
                {
                    id: "610c3b02e5e2dc586c6bfbbd",
                    key: "Project/View",
                    name: "View Project",
                    description: "permission for view Project module",
                    createdAt: "",
                    updatedAt: "",
                },
                {
                    id: "610c3b02e5e2d3w586c6bfbfs",
                    key: "Project/Add",
                    name: "Add Project",
                    description: "permission for Add Project module",
                    createdAt: "",
                    updatedAt: "",
                },
            ],
        },
    ];
    
    console.log('Permission List Before ==>', permissionList);
    
    const newList = permissionList.filter(eachObj => eachObj.name === "Database");
    console.log('New List ==>', newList);

您可以对 Javascript 中的数组执行上述 .filter() 选项

Answer 3

const permissionList = [{
    name: "Database",
    permissions: [{
        id: "610c3b02e5e2dc586c6bfbbd",
        key: "Database/View",
        name: "View Database",
        description: "permission for view database module",
        createdAt: "",
        updatedAt: "",
      },
      {
        id: "610c3b02e5e2d3w586c6bfbfs",
        key: "Database/Add",
        name: "Add Database",
        description: "permission for Add database module",
        createdAt: "",
        updatedAt: "",
      },
    ],
  },
  {
    name: "Project",
    permissions: [{
        id: "610c3b02e5e2dc586c6bfbbd",
        key: "Project/View",
        name: "View Project",
        description: "permission for view Project module",
        createdAt: "",
        updatedAt: "",
      },
      {
        id: "610c3b02e5e2d3w586c6bfbfs",
        key: "Project/Add",
        name: "Add Project",
        description: "permission for Add Project module",
        createdAt: "",
        updatedAt: "",
      },
    ],
  },
];

console.log('Permission List Before ==>', permissionList);

let permissionsOfEachObj = [];

let keys = [];

permissionList.forEach(obj => {
  keys = Object.keys(obj);
});

console.log('Keys ==>', keys);

keys.forEach((key) => {
  if(key === 'permissions') {
    permissionList.forEach(obj => {
      permissionsOfEachObj.push(obj[key]);
    })
  }
});

console.log('Permissions Of Each Object ==>', permissionsOfEachObj);

permissionsOfEachObj = permissionsOfEachObj.flat();
console.log('Permissions Of Each Object after Flatting ==>', permissionsOfEachObj);

const databaseOrView = permissionsOfEachObj.filter(eachObj => eachObj.key === "Database/View");
console.log('Final Output ==>', databaseOrView);

好的。我现在明白了这个问题。请立即在此处检查所需的输出。您拥有检查答案所需的控制台日志。

Answer 4

只有一种解决方案拒绝屈服于这种新的伪函数式编程宗教。
在这种函数中没有任何通用或可重用的东西，所以在不变性和诸如此类方面没有任何好处。没有其他人会使用它，所以它要么在此时此地起作用，要么不起作用。

与往常一样，使用纯 JavaScript 可以让您通过添加琐碎、自然的优化和安全检查来编写更快、更安全的代码，例如：

• 避免大量无用的浅拷贝
• 得到结果后缩短循环
• 禁止获得多个结果（密钥应该是唯一的）
• 禁止查询不存在的键

顺便说一句，你肯定有你的理由，但是一旦你得到一个许可，外层数据只是多余的行李。
您也可以返回实际的权限记录，有或没有（浅）副本，具体取决于您是否打算改变结果。
在这种特殊情况下，您似乎想用过滤器的结果替换初始列表，因此创建中间不可变对象是没有意义的。

function GetPermissionByKey (list, key)
{
    // if you want to check for unicity of key
    // let result = undefined;
    for (item of list) {                                     // browse all items
        for (permission of item.permissions) {               // browse all keys of each item
            if (permission.key == key) {                     // found the key
                // ...variant to enforce key uniqueness:
                // if (result !== undefined) throw 'duplicate key ' + key;
                // result = [{...item, permissions: [{...permission}]}];
                return [{...item, permissions: [{...permission}]}]; // full deep copy
                // ...or a shallow copy
                // return [{...item, permissions: [permission]}];
                // ...or you might just drop the excess luggage:
                // return permission;
                // ...or return a shallow copy if you really want one:
                // return {...permission};
            }
        }
    }
    // ...if you checked for unicity of keys
    // return result ?? []; // return an empty array if key was not found
    // ...or without unicity check
    return [];
    // ...or consider using a wrong key a program error
    // throw 'key not found ' + key;
}

使用您的示例输入的示例输出：

var res = GetPermissionByKey(permissionList,"Database/View");
console.log(`${JSON.stringify(res,undefined,2)}`)

[
  {
    "name": "Database",
    "permissions": [
      {
        "id": "610c3b02e5e2dc586c6bfbbd",
        "key": "Database/View",
        "name": "View Database",
        "description": "permission for view database module",
        "createdAt": "",
        "updatedAt": ""
      }
    ]
  }
]

Answer 5

试试这个：

const permissionList = [
        {
            name: "Database",
            permissions: [
                {
                    id: "610c3b02e5e2dc586c6bfbbd",
                    key: "Database/View",
                    name: "View Database",
                    description: "permission for view database module",
                    createdAt: "",
                    updatedAt: "",
                },
                {
                    id: "610c3b02e5e2d3w586c6bfbfs",
                    key: "Database/Add",
                    name: "Add Database",
                    description: "permission for Add database module",
                    createdAt: "",
                    updatedAt: "",
                },
            ],
        },
        {
            name: "Project",
            permissions: [
                {
                    id: "610c3b02e5e2dc586c6bfbbd",
                    key: "Project/View",
                    name: "View Project",
                    description: "permission for view Project module",
                    createdAt: "",
                    updatedAt: "",
                },
                {
                    id: "610c3b02e5e2d3w586c6bfbfs",
                    key: "Project/Add",
                    name: "Add Project",
                    description: "permission for Add Project module",
                    createdAt: "",
                    updatedAt: "",
                },
            ],
        },
    ]

console.log({name: permissionList[0].name, permissions: [permissionList[0].permissions[0]]})