วิธีแปลง JavaScript Object แบบแบน (dot notation) เป็นอ็อบเจ็กต์ซ้อนและอาร์เรย์

ภาพรวม

สมมติว่าเรามีอ็อบเจ็กต์แบบแบน (flat) ที่ใช้ dot notation:

const obj = {
  "firstName": "John",
  "lastName": "Green",
  "car.make": "Honda",
  "car.model": "Civic",
  "car.revisions.0.miles": 10150,
  "car.revisions.0.code": "REV01",
  "car.revisions.0.changes": "",
  "car.revisions.1.miles": 20021,
  "car.revisions.1.code": "REV02",
  "car.revisions.1.changes.0.type": "asthetic",
  "car.revisions.1.changes.0.desc": "Left tire cap",
  "car.revisions.1.changes.1.type": "mechanic",
  "car.revisions.1.changes.1.desc": "Engine pressure regulator",
  "visits.0.date": "2015-01-01",
  "visits.0.dealer": "DEAL-001",
  "visits.1.date": "2015-03-01",
  "visits.1.dealer": "DEAL-002"
};

เราต้องเขียนฟังก์ชันแปลงเป็นอ็อบเจ็กต์ซ้อนและอาร์เรย์

ผลลัพธ์ที่คาดหวัง

const output = {
  firstName: 'John',
  lastName: 'Green',
  car: {
    make: 'Honda',
    model: 'Civic',
    revisions: [
      { miles: 10150, code: 'REV01', changes: '' },
      { miles: 20021, code: 'REV02', changes: [
        { type: 'asthetic', desc: 'Left tire cap' },
        { type: 'mechanic', desc: 'Engine pressure regulator' }
      ]}
    ]
  },
  visits: [
    { date: '2015-01-01', dealer: 'DEAL-001' },
    { date: '2015-03-01', dealer: 'DEAL-002' }
  ]
};

ตัวอย่างโค้ด

const obj = {
  "firstName": "John",
  "lastName": "Green",
  "car.make": "Honda",
  "car.model": "Civic",
  "car.revisions.0.miles": 10150,
  "car.revisions.0.code": "REV01",
  "car.revisions.0.changes": "",
  "car.revisions.1.miles": 20021,
  "car.revisions.1.code": "REV02",
  "car.revisions.1.changes.0.type": "asthetic",
  "car.revisions.1.changes.0.desc": "Left tire cap",
  "car.revisions.1.changes.1.type": "mechanic",
  "car.revisions.1.changes.1.desc": "Engine pressure regulator",
  "visits.0.date": "2015-01-01",
  "visits.0.dealer": "DEAL-001",
  "visits.1.date": "2015-03-01",
  "visits.1.dealer": "DEAL-002"
};

const unflatten = (obj = {}) => {
  const result = {};
  let temp, substrings, property, i;
  for (property in obj) {
    substrings = property.split('.');
    temp = result;
    for (i = 0; i < substrings.length - 1; i++) {
      if (!(substrings[i] in temp)) {
        if (isFinite(substrings[i + 1])) {
          temp[substrings[i]] = [];
        } else {
          temp[substrings[i]] = {};
        }
      }
      temp = temp[substrings[i]];
    }
    temp[substrings[substrings.length - 1]] = obj[property];
  }
  return result;
};

console.log(JSON.stringify(unflatten(obj), undefined, 4));

ผลลัพธ์ในคอนโซล

{
  "firstName": "John",
  "lastName": "Green",
  "car": {
    "make": "Honda",
    "model": "Civic",
    "revisions": [
      { "miles": 10150, "code": "REV01", "changes": "" },
      { "miles": 20021, "code": "REV02", "changes": [
        { "type": "asthetic", "desc": "Left tire cap" },
        { "type": "mechanic", "desc": "Engine pressure regulator" }
      ]}
    ]
  },
  "visits": [
    { "date": "2015-01-01", "dealer": "DEAL-001" },
    { "date": "2015-03-01", "dealer": "DEAL-002" }
  ]
}