Skip to content

Providing Map#drop (by key or value) and Map#take functionality for nested maps

License

Notifications You must be signed in to change notification settings

treble37/nested_filter

Folders and files

NameName
Last commit message
Last commit date

Latest commit

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Repository files navigation

NestedFilter

Build Maintainability Test Coverage Coverage Status Hex.pm Hex.pm Downloads GitHub stars GitHub license

The Problems

  1. You have a nested map (or a struct that you converted to a nested map) and you want to remove ALL the keys with specific values such as nil.
  2. You want to do a Map#take on a nested map
Example: Remove all the map keys with nil values
nested_map = %{a: 1, b: %{c: nil, d: nil}, c: nil}

Map.drop(nested_map, [:c, :d])
# => %{a: 1, b: %{c: nil, d: nil}}

# But you actually wanted:
# => %{a: 1}

The Solution: NestedFilter

NestedFilter drills down into a nested map and can do any of the following:

  1. filters out keys according to user specified values.
  2. filters out values according to user specified keys.

Installation

If available in Hex, the package can be installed by adding nested_filter to your list of dependencies in mix.exs:

def deps do
  [{:nested_filter, "~> 1.2.2"}]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/nested_filter.

Usage

By default, when removing user specified values, empty values will be preserved (see Case 1 below). You can add empty values to the user specified values list if you wish those "empty values" (e.g., empty maps) to be removed.

NestedFilter.drop_by_value

# Case 1: Remove the nil values from a nested map, preserving empty map values

nested_map = %{a: 1, b: %{m: nil, n: 2}, c: %{p: %{q: nil, r: nil}, s: %{t: 2, u: 3}} }
NestedFilter.drop_by_value(nested_map, [nil])

# => %{a: 1, b: %{n: 2}, c: %{p: %{}, s: %{t: 2, u: 3}} }

# Case 2: Remove the nil values from a nested map, removing empty map values

nested_map = %{a: 1, b: %{m: nil, n: 2}, c: %{p: %{q: nil, r: nil}, s: %{t: 2, u: 3}} }
NestedFilter.drop_by_value(nested_map, [nil, %{}])
# => %{a: 1, b: %{n: 2}, c: %{s: %{t: 2, u: 3}} }

NestedFilter.drop_by_key

# Case 1: Remove values from a nested map by key

nested_map = %{a: 1, b: %{a: 2, b: 3}, c: %{a: %{a: 1, b: 2}, b: 2, c: %{d: 1, e: 2}}}
assert NestedFilter.drop_by_key(nested_map, [:a]) == %{b: %{b: 3},c: %{b: 2, c: %{d: 1, e: 2}}}

NestedFilter.take_by_key

# Case 1: Take values from a nested map by key

nested_map = %{a: %{b: 1}, c: 3, e: %{f: 4}}
assert NestedFilter.take_by_key(nested_map, [:b, :f]) == %{b: 1, f: 4 }

You can browse the tests for more usage examples.

About

Providing Map#drop (by key or value) and Map#take functionality for nested maps

Topics

Resources

License

Stars

Watchers

Forks

Releases

No releases published

Packages

No packages published

Languages