javascript sort array of objects by array of strings

Question

There are data structure without indexes:

const data = [{
        "B": {
            "value": 1,
        },
        "D": {
            "value": "45"
        },
        "E": {
            "value": "234"
        },
        "A": {
            "value": "543"
        },
        "C": {
            "value": "250"
        }
    }, {
        "B": {
            "value": 6,
        },
        "D": {
            "value": "234"
        },
        "E": {
            "value": "67"
        },
        "A": {
            "value": "78"
        },
        "C": {
            "value": "12"
        }
    }
   ]

and array of strings by which data array above should be sorted:

const strings = ["E", "C", "B", "A", "D"];

Is there a solution to sort data array by strings in order to get final result like:

   [{
        "E": {
            "value": "234",
        },
        "C": {
            "value": "45"
        },
        "B": {
            "value": 1
        },
        "A": {
            "value": "543"
        },
        "D": {
            "value": "250"
        }
    }...

See https://stackoverflow.com/questions/5525795/does-javascript-guarantee-object-property-order — Nenad Vracar, Jul 15 '19 at 14:46
For that you should use Map instead (which guarantee the insertion order when iterating). — Jorge Fuentes González, Jul 15 '19 at 14:47
Object string keys are ordered by insertion order - however this cannot always be guaranteed. Use an array instead — Kobe, Jul 15 '19 at 14:47
@AluanHaddad I know, that's why I said to use an array, I didn't finish my edit :) — Kobe, Jul 15 '19 at 14:48

libik · Answer 1 · 2019-07-15T14:59:15.723

yes its actually pretty easy.

const data = [{
        "B": {
            "value": 1,
        },
        "D": {
            "value": "45"
        },
        "E": {
            "value": "234"
        },
        "A": {
            "value": "543"
        },
        "C": {
            "value": "250"
        }
    }, {
        "B": {
            "value": 6,
        },
        "D": {
            "value": "234"
        },
        "E": {
            "value": "67"
        },
        "A": {
            "value": "78"
        },
        "C": {
            "value": "12"
        }
    }
   ]

const strings = ["E", "C", "B", "A", "D"];

const sorted = data.map(obj => {
  const res = {};
  strings.forEach(key => res[key] = obj[key]);
  return res;
});

console.log(sorted);

However javascript does not guarantee the order of the variables inside objects, so you should not rely on it. To have it sorted, you have to use i.e. array, which will not be an exact same data structure, but it is similar and it will ensure the sorting.

const data = [{
        "B": {
            "value": 1,
        },
        "D": {
            "value": "45"
        },
        "E": {
            "value": "234"
        },
        "A": {
            "value": "543"
        },
        "C": {
            "value": "250"
        }
    }, {
        "B": {
            "value": 6,
        },
        "D": {
            "value": "234"
        },
        "E": {
            "value": "67"
        },
        "A": {
            "value": "78"
        },
        "C": {
            "value": "12"
        }
    }
   ]

const strings = ["E", "C", "B", "A", "D"];

const sorted = data.map(obj => {
  const res = [];
  strings.forEach(key => {
    const newObj = {};
    newObj[key] = obj[key];
    res.push(newObj)
  });
  return res;
});

console.log(sorted);

Now throw a numeric key in there and see what Object.keys returns. Won't be in same order — charlietfl, Jul 15 '19 at 14:54

javascript sort array of objects by array of strings

1 Answers1