reducers.js

// Write a general-purpose reducer that excludes items based on a predicate
function excludeReducer(predicate) {
  return function(newArray, item) {
    return predicate(item) ? newArray : newArray.concat(item);
  }
}


function excludeIdReducer(id) {
  return excludeReducer(function(item) {
    return item.id === id;
  });
}

function excludeNameReducer(name) {
  return excludeReducer(function(item) {
    return item.name === name;
  });
}

var withoutFrank = array.reduce(excludeNameReducer("Frank"), []);
// excludes entity with name of Frank

var without12345 = array.reduce(excludeIdReducer("12345"), []);
// creates a new array excluding the entity with id 12345

// this is equivalent to the above
array.reduce(function(newArray, item) {
  return (item.id === "12345") ? newArray : newArray.concat(item);
}, []);