Overrides of children are not cleaned up when unregistering parent node

Describe the bug When node is unregistered then its overrides are cleaned as well, but if such node contains children that have overrides defined as well, than such overrides (those belonging to children) are not cleaned up.

To Reproduce

  test('unregistering a node should unregister the overrides of its children', () => {
    const navigation = new Lrud()

    navigation.registerNode('root')
    navigation.registerNode('a', { parent: 'root' })
    navigation.registerNode('ab', { parent: 'a' })
    navigation.registerNode('b', { parent: 'root' })

    navigation.registerOverride('override_a', {
      id: 'ab',
      direction: 'right',
      target: 'b'
    })

    navigation.unregister('a')

    expect(navigation.overrides).toEqual({})
  })

results with

 FAIL  src/unregister.test.js
  ● unregisterNode() › unregistering a node should unregister the overrides of its children

    expect(received).toEqual(expected) // deep equality

    - Expected  - 1
    + Received  + 7

    - Object {}
    + Object {
    +   "override_a": Object {
    +     "direction": "right",
    +     "id": "ab",
    +     "target": "b",
    +   },
    + }

       |     navigation.unregister('a')
       |
    >  |     expect(navigation.overrides).toEqual({})
       |                                  ^
       |   })
       |

Expected behavior Expected behavior is that all overrides related to unregistered node and its children should be cleaned up.

Screenshots No screenshots.

Additional context No additional context.

bbc / lrud

Overrides of children are not cleaned up when unregistering parent node #86