Angular 8: Remove empty Object from array

Question

Im using Angular8, want to remove empty object from an array, and get its length

Array: [
{data01: "abc", data02: "cde", data03: "fgh", data04: "", data05: ""},
{data01: "abc", data02: "cde", data03: "", data04: "", data05: ""},
{data01: "abc", data02: "cde", data03: "fgh", data04: "ijk", data05: "lmn"},
{data01: "abc", data02: "", data03: "", data04: "", data05: ""},
]

then I want it be like

Array: [
{data01: "abc", data02: "cde", data03: "fgh"},
{data01: "abc", data02: "cde"},
{data01: "abc", data02: "cde", data03: "fgh", data04: "ijk", data05: "lmn"},
{data01: "abc"},
]

is that anyway to do it ?

I tried to push those element in a new array like

_Array: ["abc","cde", "fgh", "", "", ....] 

and chunk it by 5 then filter(Boolean), it works, but the performance was bit slow, any other way to improve the performance?

Answer 1

You can use the map() and filter() of Array object methods in JS to solve the problem.

let array = [
{data01: "abc", data02: "cde", data03: "fgh", data04: "", data05: ""},
{data01: "abc", data02: "cde", data03: "", data04: "", data05: ""},
{data01: "abc", data02: "cde", data03: "fgh", data04: "ijk", data05: "lmn"},
{data01: "abc", data02: "", data03: "", data04: "", data05: ""},
]; // array provided

array = array.map(object => {
          let entries = Object.entries(object); //for each element in the array get the entries, [key, value] pair
          entries = entries.filter(([key, value]) => value !== ""); // remove the elements which has "" values
          return Object.fromEntries(entries);
          });
console.log(array.length);
// shorter version
array = array.map(object => Object.fromEntries(Object.entries(object).filter(([key, value]) => value !== "")));
console.log(array.length);

There is a possibility the resultant array might contain an empty object if the input array had a object which had all the entries ""(empty string). Eg: {data01: "", data02: "", data03: "", data04: "", data05: ""}. In this case we need another filter() to remove the empty object from the resultant array.

let array = [
    {data01: "abc", data02: "cde", data03: "fgh", data04: "", data05: ""},
    {data01: "abc", data02: "cde", data03: "", data04: "", data05: ""},
    {data01: "abc", data02: "cde", data03: "fgh", data04: "ijk", data05: "lmn"},
    {data01: "abc", data02: "", data03: "", data04: "", data05: ""},
    ]; // array provided

    array = array.map(object => {
              let entries = Object.entries(object);
              entries = entries.filter(([key, value]) => value !== "");
              return Object.fromEntries(entries);
              });
    // remove the empty object if present
    array = array.filter(object => Object.entries(object).length !== 0);
    console.log(array.length);
    // shorter version
    array = array.map(object => Object.fromEntries(Object.entries(object).filter(([key, value]) => value !== ""))).filter(object => Object.entries(object).length !== 0);
    // the filter() at the  end removes the empty object
    console.log(array.length);