How to filter tree-like named object?

Question

I have a tree object like below, and I need to search through it. I know there's already some answers on topics like this here, but they are, unfortunately, do not comply with my structure.

const tree = {
    "28": {
        "label": "lorem"
        "children": {
            "188": {
                "label": "ipsum"
                "children": {
                    "482": {
                        "label": "fish"
                        "children": {
                            "185": {
                                "label": "dog"
                            },
                            "289": {
                                "label": "cat"
                            }
                        }
                    }
                }
            }
        }
    },
    "33": {
        "label": "water"
        "children": {
            "95": {
                "label": "fire"
                "children": {
                    "181": {
                        "label": "gas"
                        "children": {
                            "100": {
                                "label": "station"
                            }
                        }
                    }
                    "182": {
                        "label": ""
                        "children": {
                            "100": {
                                "label": "sushi"
                            }
                        }
                    }
                }
            }
        }
    }
}

For example, if I'll search for 'fish', output should be like this:

{
    "28": {
        "label": "lorem"
        "children": {
            "188": {
                "label": "ipsum"
                "children": {
                    "482": {
                        "label": "fish"
                        "children": {
                            "185": {
                                "label": "dog"
                            },
                            "289": {
                                "label": "cat"
                            }
                        }
                    }
                }
            }
        }
    }
}

And if I'll search for 'dog' instead:

{
    "28": {
        "label": "lorem"
        "children": {
            "188": {
                "label": "ipsum"
                "children": {
                    "482": {
                        "label": "fish"
                        "children": {
                            "185": {
                                "label": "dog"
                            }
                        }
                    }
                }
            }
        }
    }
}

I tried to use these answers, but couldn't adapt them to named objects:

How to filter a tree structure while keeping the decendants of the parents that are filtered out?

A Javascript function to filter tree structured json with a search term. exclude any object which donot match the search term

Answer 1

1. Use a recursive function that searches in the children property recursively.
2. Since you mentioned "filter", we should support finding multiple results.
3. For more flexibility we could provide a callback like in Array::filter().
4. Note that we don't use here spread syntax and functional approach since it would be slower.

const search = (obj, cb) => {

  let out = null;

  for(const key in obj){
  
    const item = obj[key];
    
    if(cb(item)){
      (out ??= {})[key] = item;
      continue;
    }
    
    if(item.children){
      const found = search(item.children, cb);
      if(found){
        (out ??= {})[key] = Object.assign({}, item, {children: found});
      }
    }
  }
  
  return out;

};

[
  item => item.label === 'fish',
  item => item.label === 'dog',
  item => ['dog', 'station'].includes(item.label),
  item => false
].forEach(cb => $pre.insertAdjacentHTML('beforeend', cb + ': ' + JSON.stringify(search(tree, cb), null, 4) + '\n'));

<script>
const tree = {
    "28": {
        "label": "lorem",
        "children": {
            "188": {
                "label": "ipsum",
                "children": {
                    "482": {
                        "label": "fish",
                        "children": {
                            "185": {
                                "label": "dog"
                            },
                            "289": {
                                "label": "cat"
                            }
                        }
                    }
                }
            }
        }
    },
    "33": {
        "label": "water",
        "children": {
            "95": {
                "label": "fire",
                "children": {
                    "181": {
                        "label": "gas",
                        "children": {
                            "100": {
                                "label": "station"
                            }
                        }
                    },
                    "182": {
                        "label": "",
                        "children": {
                            "100": {
                                "label": "sushi"
                            }
                        }
                    }
                }
            }
        }
    }
}
</script>
<pre id="$pre"></pre>