CODEWITHSUNDEEP
javascriptarrays
Salma Elshahawy
Salma Elshahawy

Reputation: 1190

changing from array list to an object javascript

I have a problem with my code as when I increase the number of elements inside the array it runs only the last added 3 elements only not the full list I don't know what's wrong in my code. please help!

var array = [
  ['make', 'Ford'],
  ['model', 'Mustang'],
  ['year', '1964'],
  ['make', 'Honda'],
  ['model', 'CRV'],
  ['year', '2000']
];

function fromListToObject(array) {
  var obj = Object.create(null); // empty container for my object
  for (var i = 0; i < array.length; i++) { //declare the 1st array loop
    var arr1 = array[i]; //decleare the nested array
    obj[arr1[0]] = arr1[1]; //1st item = 2nd item in the nested array
  }
  return obj;
}

var result = fromListToObject(array);
console.log(result);

Upvotes: 1

Views: 92

Answers (4)

H77
H77

Reputation: 5967

Does this give you the output you're looking for?

var array = [
  ['make', 'Ford'],
  ['model', 'Mustang'],
  ['year', '1964'],
  ['make', 'Honda'],
  ['model', 'CRV'],
  ['year', '2000']
];

function fromListToObject(data) {
  var cars = [];
  for (var i = 0; i < data.length; i++) {
    var car = {};
    car[data[i][0]] = data[i++][1];
    car[data[i][0]] = data[i++][1];
    car[data[i][0]] = data[i][1];
    cars.push(car);
  }
  return cars;
}

var result = fromListToObject(array);
console.log(result);

Update: Version 2

var array = [
  ['make', 'Ford'],
  ['model', 'Mustang'],
  ['year', '1964'],
  ['make', 'Honda'],
  ['model', 'CRV'],
  ['year', '2000']
];

function fromListToObject(data) {
  var cars = [];

  var car = {};
  data.forEach(function(item) {
    if (item.length < 2)
      return;

    var key = item[0];

    // the car already has the key, so this must be new
    // add the car to the list and create a new one.
    if (car.hasOwnProperty(key)) {
      cars.push(car);
      car = {};
    }

    car[key] = item[1];
  });

  // add the last car in
  cars.push(car);
  return cars;
}

var result = fromListToObject(array);
console.log(result);

Upvotes: 1

uingtea
uingtea

Reputation: 6524

return full object

{ 
'0': { make: 'Ford', model: 'Mustang', year: '1964' },
'1': { make: 'Honda', model: 'CRV', year: '2000' }
}


var array = [
  ['make', 'Ford'],
  ['model', 'Mustang'],
  ['year', '1964'],
  ['make', 'Honda'],
  ['model', 'CRV'],
  ['year', '2000']
];

function fromListToObject(array) {
  var obj = {};
  var child_obj = {};
  var objindex = 0;
  var index = 0;
  while(array.length) {
    while(array.length && index < 3){
      var arr1 = array.shift();
      child_obj[arr1[0]] = arr1[1];
      index++;
    }
    index = 0;
    obj[objindex]= child_obj;
    child_obj = {};
    objindex++;
  }
  return obj;
}

var result = fromListToObject(array);
console.log(result);

Upvotes: 0

baao
baao

Reputation: 73231

You have to get the data into an array of objects. I'd chunk the original array into pieces of the then keys size, then handle those chunks and create individual objects for them. Note that below will fail if the original array contains chunks that are not equal (keys missing, e.g.), so you will need to add a check for that or be really sure that the original array is always correct:

let array = [
  ['make', 'Ford'],
  ['model', 'Mustang'],
  ['year', '1964'],
  ['make', 'Honda'],
  ['model', 'CRV'],
  ['year', '2000']
];

function toArrOfObj(array) {
  let keys = [...new Map(array).keys()];
  let i, j, res = [], chunk = keys.length;
  for (i = 0, j = array.length; i < j; i += chunk) {
    let tmp = array.slice(i, i + chunk);
    let obj = {};
    for (let [k, v] of tmp) {
      obj[k] = v;
    }
    res.push(obj);
  }
  return res;
}

console.log(toArrOfObj(array));

Upvotes: 1

Hassan Imam
Hassan Imam

Reputation: 22534

var array = [['make', 'Ford'], ['model', 'Mustang'], ['year', '1964'],['make', 'Honda'], ['model', 'CRV'], ['year', '2000']];


function fromListToObject(array) {  
  var cars = [];
    for(var j = 0; j < array.length/3; j++){ 
      var obj = {};
      for (var i = j; i <= j+3; i++) { 
        var arr1 = array[i];
        obj[arr1[0]] = arr1[1];
      }
      cars.push(obj)
    }
  return cars;
}

var output = fromListToObject(array);
console.log(output);

Upvotes: 0

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