This is a function I wanted to keep somewhere until I found the library that did it better or had the time to implement ramdajs. It takes a couple functions and an array of objects. It returns an array of objects / values / results based on a unique value.

unique-array-from-object-array.js

/* ok, ok, I needed a way to get unique values from objects
   getUniqueIdFun should be a function that returns the value of what
    you want to be unique
   getUniquePartFun should be a function that returns the part of the
    object you are interested in; it can be undefined, null, empty if
    you want the whole object back
   objAr should be an array of objects to cull from
*/
const getUniqueObjectsFromArray = (getUniqueIdFun, getUniquePartFun, objAr) => {
  const getU = (typeof getUniquePartFun === 'function') ?
    getUniquePartFun : o => o;
  return objAr.reduce((soFar, obj) => {
    const uniqueIdOfObject = getUniqueIdFun(obj);
    const uniquePart = getU(obj);
    return soFar.uniqueIds.indexOf(uniqueIdOfObject) >= 0 ?
      soFar :
      { uniqueIds: soFar.uniqueIds.concat([uniqueIdOfObject]),
        uniqueParts: soFar.uniqueParts.concat([uniquePart])};
  }, {uniqueIds: [], uniqueParts: []}).uniqueParts;
};