Added keepInArray hook to keep fields from a nested array

[dekelev]

Problem

The keep hook does a great job for its intended purpose, but it won't work for nested arrays. for example, finding a record with one-to-many or many-to-many ORM relations.

Solution

This new keepInArray hook works like keep, but it accepts 2 arguments. the first is a dot notation string type field and the second is an array of field names to keep from it.

Usage

Data structures:

{ 
  users: [
    {
      name: 'John',
      secret: 'doNotKeep',
      dept: 'Accounting',
      address: {
        city: 'New York',
        secret: 'doNotKeep'
      }
    }
  ],
  owner: 'Jane Doe'
}

{
  account: {
    users: [
      {
        name: 'John',
        secret: 'doNotKeep',
        dept: 'Accounting',
        address: {
          city: 'New York',
          secret: 'doNotKeep'
        }
      }
    ],
    owner: 'Jane Doe'
  }
}

Using hook:

const { keepInArray } = require('feathers-hooks-common');
    
module.exports = { after: {
  create: keepInArray('users', ['name', 'dept', 'address.city']),
  find: keepInArray('account.users', ['name', 'dept', 'address.city']),
} };

Data structures after using hook:

{ 
  users: [
    {
      name: 'John',
      dept: 'Accounting',
      address: {
        city: 'New York'
      }
    }
  ],
  owner: 'Jane Doe'
}

{
  account: {
    users: [
      {
        name: 'John',
        dept: 'Accounting',
        address: {
          city: 'New York'
        }
      }
    ],
    owner: 'Jane Doe'
  }
}

Added tests and PR to the feathers-plus docs.

[eddyystop]

First of all, great job figuring out how to change the docs, and following the repo standards for the hook code.

Dot notation and arrays have been a quandry. In the general case of a.b.c.d.e both b and d may be arrays. I did not want to start dealing with multiple arrays.

Am I correct in thinking your hook will throw on line 22 if field is not an array? Would it be helpful if an explicit error identifying the problem is thrown instead?

Your comments are welcome, and let me think on this also.

[dekelev]

@eddyystop the code will now throw a BadRequest error when the field param is leading to a non-empty & non-array object type.

[eddyystop]

I think the more clear a name is, the more likely a hook is to be found by users. Would you mind changing the name to keepInArray? I'll merge thereafter.

[dekelev]

@eddyystop sure, name changed to keepInArray (also in the docs PR)

[eddyystop]

Published as 4.16.0