How to Best Sort an Array of Objects by Property or Method?

Question

I am writing a function that will sort an array of objects either by property or method value. The following code is working. But how do I improve it? I feel there is a lot of duplicate code in it.

 transform(array: any, field: string): any[] {
  if (!Array.isArray(array)) {
    return;
  }
  array.sort((a: any, b: any) => {
    if (typeof a[field] == 'function' && typeof b[field] == 'function') {
      if (a[field]() < b[field]()) {
        return -1;
      } else if (a[field]() > b[field]()) {
        return 1;
      } else {
        return 0;
      }
    }
    if (a[field] < b[field]) {
      return -1;
    } else if (a[field] > b[field]) {
      return 1;
    } else {
      return 0;
    }
  });
  return array;
}

Answer 1

  const callOrTake = it => typeof it === "function" ? it() : it;  
  const compare = (a, b) => a === b ? 0 : (a > b ? 1 : -1); 
  const transform = <T> (array: T[], field: keyof T) => array.sort((a, b) => compare(callOrTake(a[field]), callOrTake(b[field])));

The following improvements were made:

(1) Calling the field if it is a function was moved to it's own function to avoid repetition.

(2) The signature of transform was improved so that field cannot be any string, but has to be a key of whatever is inside the array.