Defer dictionary item setter to run a custom function on change. Used by background callback manager to save the `set_props` data.
| 1 | class ProxySetProps(dict): |
| 2 | """ |
| 3 | Defer dictionary item setter to run a custom function on change. |
| 4 | Used by background callback manager to save the `set_props` data. |
| 5 | """ |
| 6 | |
| 7 | def __init__(self, on_change): |
| 8 | super().__init__() |
| 9 | self.on_change = on_change |
| 10 | self._data = {} |
| 11 | |
| 12 | def __setitem__(self, key, value): |
| 13 | self.on_change(key, value) |
| 14 | self._data.setdefault(key, {}) |
| 15 | self._data[key] = {**self._data[key], **value} |
| 16 | |
| 17 | def get(self, key, default=None): |
| 18 | return self._data.get(key, default) |