CODEWITHSUNDEEP
javascriptobjectmergelodash
Denis
Denis

Reputation: 143

Merge javascript objects in object with same value

I have been trying to combine objects with same value. The object that I have is like this:

{
  'Mon': [{'apple': 'A', 'color': 'green'}, {'apple':'B', 'color':'yellow'}],
  'Tue': [{'apple': 'A', 'color': 'green'}, {'apple':'B', 'color':'yellow'}],
  'Wed': [],
  'Thu': [],
  'Fri': [{'banana': 'A', 'color': 'yellow'}],
  'Sat': [{'banana': 'A', 'color': 'yellow'}],
  'Sun': [{'banana': 'A', 'color': 'yellow'}]
}

I have been trying to find a way to combine these so that the result would be like this:

{
  ['Mon', 'Tue']: [{'apple': 'A', 'color': 'green'}, {'apple':'B','color':'yellow'}],
  ['Wed', 'Thu']: [],
  ['Fri','Sat','Sun']: [{'banana': 'A', 'color': 'yellow'}]
}

Is there some way to do this with lodash ? or pure js ?

Upvotes: 0

Views: 691

Answers (1)

rpadovani
rpadovani

Reputation: 7360

In Javascript the keys of an object have to be strings.

However, you can use arrays, they will be casted to string:

var a = {};

a[['Mon', 'Tue']] = 1;

console.log(a[['Mon', 'Tue']])
console.log(a)

But, of course, they keys of the final object would be string. Anyway, should be trivial to create a function to convert them back to array, if you need them.

About processing the data, I'd go like this:

var original = {
  'Mon': [{'apple': 'A', 'color': 'green'}, {'apple':'B', 'color':'yellow'}],
  'Tue': [{'apple': 'A', 'color': 'green'}, {'apple':'B', 'color':'yellow'}],
  'Wed': [],
  'Thu': [],
  'Fri': [{'banana': 'A', 'color': 'yellow'}],
  'Sat': [{'banana': 'A', 'color': 'yellow'}],
  'Sun': [{'banana': 'A', 'color': 'yellow'}]
};

var emptyKey = [];

function createId(o) {
  var values = [];
  
  for (let x in o) {
    if (o.hasOwnProperty(x)) {
      values.push(o[x])
    }
  }
  return Object.keys(o).sort().toString() + values.sort().toString();
}

var uniqueValues = [];

for (let d in original) {
  for (let b in original[d]) {
    let idx = createId(original[d][b]);
    if (uniqueValues.indexOf(idx) === -1) uniqueValues.push(idx);
  }

  if (Object.keys(original[d]).length === 0) emptyKey.push(d);
}

var result = {};

for (let u in uniqueValues) {
  let k = [];
  let o = null;
  
  for (let d in original) {
    for (let b in original[d]) {
      let idx = createId(original[d][b]);
      if (uniqueValues[u] === idx) {
        k.push(d);
        o = original[d][b];
      }
    }
  }
  
  if (k.length > 0) {
     result[k] = result[k] || [];
     result[k].push(o);
  }
}

if (emptyKey.length > 0) result[emptyKey] = [];

console.log(result)

However, some caveats of the solution:

  • As said, keys are string, not arrays, but anyway you can access them using arrays (because they have the toString() method).
  • The order in which the keys are printed is theoretical not guaranteed, and this is why I use the sort() method - also if all the major browsers will print them in the order they are inserted

Upvotes: 1

Related Questions