Native Javascript - Merge Two Arrays Of Objects

I want to merge two array like : arr1 = [ ['01/09',1], ['02/09',2], ['03/09',3], ['04/09',4] ]; arr2 = [ ['01/09',13], ['03/09',14], ['04/09',15],

Solution 1:

You could use a combined approach to build the empty array with the parameters adn iterate and build a hash table for the matched items. Then apply the value.

functionmerge(arrays) {
    var hash = Object.create(null),
        merged = [];

    arrays.forEach(function (a, i) {
        a.forEach(function (b) {
            if (!hash[b[0]]) {
                hash[b[0]] = Array.apply(null, { length: arrays.length + 1 }).map(function () { return0 });
                hash[b[0]][0] = b[0];
                merged.push(hash[b[0]]);
            }
            hash[b[0]][i + 1] = b[1];
        });
    });
    return merged;
}

var arr1 = [['01/09', 1], ['02/09', 2], ['03/09', 3], ['04/09', 4]],
    arr2 = [['01/09', 13], ['03/09', 14], ['04/09', 15], ['05/09', 16]];

console.log(merge([arr1, arr2]));

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Solution 2:

You can use Array.find to search in array and then use Array.concat to merge them.

Array.find + array.concat

var arr1 = [
  ['01/09', 1],
  ['02/09', 2],
  ['03/09', 3],
  ['04/09', 4]
];

var arr2 = [
  ['01/09', 13],
  ['03/09', 14],
  ['04/09', 15],
  ['05/09', 16]
];

var result = arr1.map(function(a1) {
  var _tmp = arr2.find(x => x[0] === a1[0]) || [];
  return a1.concat(_tmp.splice(1));
});

console.log(result)

Though, I would suggest you to use following structure as it would be more scalable.

Map object

var arr1 = [
  ['01/09', 1],
  ['02/09', 2],
  ['03/09', 3],
  ['04/09', 4]
];

var arr2 = [
  ['01/09', 13],
  ['03/09', 14],
  ['04/09', 15],
  ['05/09', 16]
];
var result = {};
arr1.forEach(function(item) {
  result[item[0]] = item.slice(1) || [];
});

arr2.forEach(function(item) {
  result[item[0]] = result[item[0]] || [];
  result[item[0]] = result[item[0]].concat(item.slice(1))
});

console.log(result)

Few pointers,

• array.concat will return merged string but will not update the variable. So don't forget to assign it.
• array.find has compatibility issues. Do check them before using it. You can also use array.filter as an alternative.

Solution 3:

var arr1 = [
  ['01/09', 1],
  ['02/09', 2],
  ['03/09', 3],
  ['04/09', 4]
];

var arr2 = [
  ['01/09', 13],
  ['03/09', 14],
  ['04/09', 15],
  ['05/09', 16]
];

var arr3 = [
  ['01/09', 130],
  ['03/09', 140],
  ['04/09', 150],
  ['05/09', 160]
];


functionmergeArrays() {
  var resultObj = {},
    resultArray = [];
  var array = Array.prototype.concat.apply([], Array.prototype.slice.call(arguments));
  array.map(function(item) {
    var key = item[0];
    if (!this[key]) {
      this[key] = [];
      this[key].push(key);
    }
    this[key].push(item[1]);
  }, resultObj);

  for (var key in resultObj) {
    resultArray.push(resultObj[key]);

  }
  return resultArray;
}
console.log(mergeArrays(arr1, arr2, arr3));

Solution 4:

You could do this with reduce() and forEach()

var arr1 = [
  ['01/09', 1],
  ['02/09', 2],
  ['03/09', 3],
  ['04/09', 4]
];
var arr2 = [
  ['01/09', 13],
  ['03/09', 14],
  ['04/09', 15],
  ['05/09', 16]
];

var obj = {}
var result = arr1.reduce(function(r, e) {

  arr2.forEach(function(el, i) {
    if (!obj[e[0]]) {
      obj[e[0]] = [e[0], 0, 0];
      r.push(obj[e[0]]);
    }

    obj[e[0]][1] = e[1];
    if (el[0] == e[0]) {
      obj[e[0]][2] = el[1];
    } else {
      if (!obj[el[0]]) {
        obj[el[0]] = [el[0], 0, el[1]];
        r.push(obj[el[0]]);
      }
    }
  })

  return r;
}, []);

console.log(result)