將平面數據轉換爲具有內部對象的層次結構javascript

Question

我面臨將簡單平面數據轉換爲層次結構的常見問題。我發現有關多個主題，但仍然不能得到如何平數據轉換正好給我必要的分層格式

這是我的JSON

[ 
    { 
    "id": 1, 
    "name": "Sponsor", 
    "description": null, 
    "parentId": null 
    }, 
    { 
    "id": 2, 
    "name": "Class", 
    "description": null, 
    "parentId": 1 
    }, 
    { 
    "id": 3, 
    "name": "Study", 
    "description": null, 
    "parentId": 2 
    }, 
    { 
    "id": 4, 
    "name": "Site", 
    "description": null, 
    "parentId": 3 
    } 
] 

，我需要得到格式這樣

[ 
    { 
     "data":{ 
     "id": 1, 
     "name":"Sponsor", 
     "description":null, 
     "parentId":"null" 
     }, 
     "children":[ 
     { 
      "data":{ 
      "id": 2, 
      "name":"Class", 
      "description":null, 
      "parentId":"1" 
      }, 
      "children":[ 
      { 
       "data":{ 
       "id": 3, 
       "name":"Study", 
       "description":null, 
       "parentId":"2" 
       }, 
      "children": [ 
       { 
        "data":{ 
        "id": 4, 
        "name":"Site", 
        "description":null, 
        "parentId":"3" 
        } 
       } 
       ] 
      } 
      ] 
     } 
     ] 
    } 
    ] 

這是我的功能

flatToHierarchy(flat) { 

    let roots = []; 
    let all = {}; 

    flat.forEach(function (item) { 
     all[item.id] = item 
    }); 

    Object.keys(all).forEach(function (id) { 
     let item = all[id]; 
     if (item.parentId === null) { 
     roots.push(item) 
     } else if (item.parentId in all) { 
     let p = all[item.parentId]; 
     if (!('Children' in p)) { 
      p.children = [] 
     } 
     p.children.push(item) 
     } 
    }); 

    console.log(roots); 
    return roots 
    } 

輸出

[ 
    { 
    "id": 1, 
    "name": "Sponsor", 
    "description": null, 
    "parentId": null, 
    "children": [ 
     { 
     "id": 2, 
     "name": "Class", 
     "description": "Together", 
     "parentId": 1, 
     "children": [ 
      { 
      "id": 3, 
      "name": "Study", 
      "description": "browsing data", 
      "parentId": 2, 
      "children": [ 
       { 
       "id": 4, 
       "name": "Site", 
       "description": null, 
       "parentId": 3, 
       "children": [] 
       } 
      ] 
      } 
     ] 
     } 
    ] 
    } 
    ] 

我很接近渴望的結果。有人能幫我解決這個問題嗎？

編輯

通過@ Someone3 提供正確的答案，這是稍微修改代碼爲我的需求

flatToHierarchy (flat) { 

    let roots = []; 
    let all = {}; 
    let ids = []; 

    flat.forEach(function (item) { 
     let itemId = item.id; 
     let convertedItem = function (id) { 
     let newItem = {}; 
     newItem['data'] = id; 
     return newItem; 
     } ; 
     all[itemId] = convertedItem(item); 
     ids.push(itemId); 
    }); 

    for (let i = 0; i < ids.length; i++) { 
     let id = ids[i]; 
     let convertedItem = all[id]; 
     let parentId = convertedItem.data.parentId; 

     if (parentId === null) { 
     roots.push(convertedItem); 
     } else if (parentId in all) { 
     let p = all[parentId]; 
     if (!('children' in p)) { 
      p.children = [] 
     } 
     p.children.push(convertedItem) 
     } 
    } 
    return roots 
    } 

Answer 1

下面的代碼是適合自己情況的全部源代碼。我修改並添加了幾行代碼。 請注意，此代碼假定父母總是在他們的孩子之前插入此樹。如果這個假設並不總是如此，那麼你的代碼需要改變更多。

let flatData = [ 
    { 
    "id": 1, 
    "name": "Sponsor", 
    "description": null, 
    "parentId": null 
    }, 
    { 
    "id": 2, 
    "name": "Class", 
    "description": null, 
    "parentId": 1 
    }, 
    { 
    "id": 3, 
    "name": "Study", 
    "description": null, 
    "parentId": 2 
    }, 
    { 
    "id": 4, 
    "name": "Site", 
    "description": null, 
    "parentId": 3 
    } 
]; 

function convertItem(item) { 
    let newItem = {}; 
    newItem.data = item; 
    return newItem; 
} 

function flatToHierarchy(flat) { 

    let roots = []; 
    let all = {}; 
    let ids = []; 

    flat.forEach(function (item) { 
     let itemId = item.id; 
     let convertedItem = convertItem(item); 
     all[itemId] = convertedItem; 
     ids.push(itemId); 
    }); 

    // We use ids array instead of object to maintain its previous order. 
    for (let i = 0; i < ids.length; i++) { 
     let id = ids[i]; 
     let convertedItem = all[id]; 
     let parentId = convertedItem.data.parentId; 

     if (parentId === null) { 
     delete convertedItem.data.parentId; 
     delete convertedItem.data.id; 
     roots.push(convertedItem); 
     } else if (parentId in all) { 
     let p = all[parentId]; 
     if (!('Children' in p)) { 
      p.children = [] 
     } 
     delete convertedItem.data.parentId; 
     delete convertedItem.data.id; 
     p.children.push(convertedItem) 
     } 
    }; 

    console.log(roots); 
    return roots 
    } 

    flatToHierarchy(flatData); 

我們可以在推送前分解兩個刪除。