converting object of arrays to an array of objects in a desired format

Question

const getSelectedItemsIds = selectedItemsList => {

  let keys = Object.keys(selectedItemsList);
  let selectedItems = [];

  keys.map(k => {
    selectedItemsList[k].map(id => {
      if (k.includes("projectIds")) {
        return selectedItems.push({ type: "PROJECT", id });
      } else if (k.includes("subjectGroupIds")) {
        return selectedItems.push({
          type: "SUBJECT_GROUP",
          id
        });
      } else if (k.includes("subjectIds")) {
        return selectedItems.push({ type: "SUBJECT", id });
      }
    });
  });

  return selectedItems;
}

I have written my custom logic to get the desired result, if anyone can validate and tell me if there's a better way to do it. I'm adding input and expected out below:

I/P: 
{
    projectIds: [2]
    subjectGroupIds: [] // incase multiple subjects are grouped togehter
    subjectIds: [4]
}

Expected format:
[{"type":"PROJECT","id":2},{"type":"SUBJECT","id":4}]

Thanks in advance!

Answer 1

Your code is not bad. You use functional style to loop through the data, which is good. But inside the loop you do not have to check with if-elseif-elseif, as this is not solid when it comes to many many cases. Maybe it would be better to use a map object to guide the process of matching data.

getSelectedItemsIds = selectedItemsList => {
    const keyNamesMap = {
        projectIds: "PROJECT",
        subjectGroupIds: "SUBJECT_GROUP",   
        subjectIds: "SUBJECT"
    };
    let selectedItems = [];

    Object.keys(keyNamesMap).map( k => {
        selectedItemsList[k].map ( id => {
            selectedItems.push (
                {
                    type: keyNamesMap[k],
                    id: id
                }
            );
        });       
    });
    return selectedItems;
}

This way it is more clear and more easy to add another type.