flatten array of objects with dynamic keys and sum only values with “_abs” in key name

I have an array of objects that looks like this:

[{"A_abs":4,"A_perc":2, "B_abs":4,"B_perc":2, ...},{"A_abs":4,"A_perc":2, "B_abs":4,"B_perc":2, ...},{"A_abs":4,"A_perc":2, "B_abs":4,"B_perc":2, ...},{"A_abs":4,"A_perc":2, "B_abs":4,"B_perc":2, ...}]

There can be up to n elements in each object, each one consists of a _perc and an _abs value. I want to reduce the array to only 1 entry and sum each _abs value, the _perc can be anything else, like “-“.

An expected result would be:

{"A_abs": 16, "A_perc": "-" "B_abs": 16, "B_perc": "-"  "C_abs": x, "C_perc": "-", ...}

The solution of this question does not fully statisfy me because I don’t know how to adapt the function to only sum the “_abs” values.

How to adapt this function to only sum the _abs values, regardles of how many entries the object has?

var data = [{"A_abs":4,"A_perc":2, "B_abs":4,"B_perc":2},{"A_abs":4,"A_perc":2, "B_abs":4,"B_perc":2},{"A_abs":4,"A_perc":2, "B_abs":4,"B_perc":2},{"A_abs":4,"A_perc":2, "B_abs":4,"B_perc":2}],
    result = data.reduce((r, o) => (Object.entries(o).forEach(([k, v]) => r[k] = (r[k] || 0) + v), r), {});

console.log(result);

Answer

You can check if the key ends with _abs and only if it does you add the values else you simply assign a value of -.

const data = [
    { A_abs: 4, A_perc: 2, B_abs: 4, B_perc: 2 },
    { A_abs: 4, A_perc: 2, B_abs: 4, B_perc: 2 },
    { A_abs: 4, A_perc: 2, B_abs: 4, B_perc: 2 },
    { A_abs: 4, A_perc: 2, B_abs: 4, B_perc: 2 },
  ],
  result = data.reduce(
    (r, o) => (
      Object.entries(o).forEach(([k, v]) =>
        k.endsWith("_abs") ? (r[k] = (r[k] || 0) + v) : (r[k] = "-")
      ),
      r
    ),
    {}
  );

console.log(result);