const sampleArray = [
  {
    numProp: 5,
    alphaProp: 'Foo',
    charProp: 'e'
  },
  {
    numProp: 4,
    alphaProp: 'Bar',
    charProp: 'a'
  },
  {
    numProp: 7,
    alphaProp: 'Baz',
    charProp: 'd'
  },
  {
    numProp: 9,
    alphaProp: 'Qux',
    charProp: 'g'
  }
];

const numericSort = prop => ({[prop]: a}, {[prop]: b}) => a - b;

const alphaSort = prop => ({[prop]: a}, {[prop]: b}) => a < b ? -1 : 1;

const weirdCustomSort = prop => ({[prop]: a}, {[prop]: b}) => {
  const elements = ['a','e','b','d','c'];
  const aIndex = ~elements.indexOf(a) ? elements.indexOf(a) : elements.length;
  const bIndex = ~elements.indexOf(b) ? elements.indexOf(b) : elements.length;
  return aIndex - bIndex;
};



const compareBy = prop => sortFunc => sortFunc(prop);

const numSortedArray = [...sampleArray].sort(compareBy('numProp')(numericSort));
const alphaSortedArray = [...sampleArray].sort(compareBy('alphaProp')(alphaSort));
const customSortedArray = [...sampleArray].sort(compareBy('charProp')(weirdCustomSort));