MaxDiff

MaxDiff(items)

An implementation of the MaxDiff technique to support the discrete ordering model.

argument	description
items	An iterable of the items to order.

Returns an instance to control the process.

demo

Try it out!

dependencies

• BronKerbosch

setup

npm

npm i @seregpie/max-diff

---

Import inside an ES module.

import MaxDiff from '@seregpie/max-diff';

or

Import inside a CommonJS module.

let MaxDiff = require('@seregpie/max-diff');

browser

<script src="https://unpkg.com/@seregpie/bron-kerbosch"></script>
<script src="https://unpkg.com/@seregpie/max-diff"></script>

The module is globally available as MaxDiff.

usage

let instance = MaxDiff(items);
while (!instance.complete) {
  let orderableItems = instance.getCandidates();
  let [bestItem, worstItem] = pickTwo(orderableItems);
  instance.orderBefore(bestItem, orderableItems);
  instance.orderAfter(worstItem, orderableItems);
}
console.log(instance.result);

members

.items

read-only

An array as the items to order.

---

.complete

read-only

A boolean indicating whether the process is complete.

---

.progress

read-only

A number indicating the progress of the process. The range is between 0 to 1.

---

.result

read-only

An array of the items in the resulted order. The property is only valid if the process is complete.

---

.order(...items)

Orders the items in the given order of the arguments.

Already established comparisons between the items are immutable.

argument	description
...items	Each argument is an item to order.

let instance = MaxDiff(['a', 'b', 'c', 'd', 'e']);
instance.order('e', 'd', 'c');
instance.order('c', 'b', 'a');
console.log(instance.result); // => ['e', 'd', 'c', 'b', 'a']

---

.getCandidates(limit = 4)

Gets the items that are the most significant candidates to be ordered as next.

argument	description
limit	A number as the limit of the candidates to get.

Returns an array.

---

.orderBefore(item, otherItems)

Orders an item before the other items.

Already established comparisons between the items are immutable.

argument	description
item	The item to order before the other items.
otherItems	An iterable of the other items to order after the item.

let instance = MaxDiff(['a', 'b', 'c']);
instance.orderBefore('c', ['a', 'b']);
console.log(instance.getOrderedPairs()); // => [['c', 'a'], ['c', 'b']]

---

.orderAfter(item, otherItems)

Orders an item after the other items.

Already established comparisons between the items are immutable.

argument	description
item	The item to order after the other items.
otherItems	An iterable of the other items to order before the item.

let instance = MaxDiff(['a', 'b', 'c']);
instance.orderAfter('a', ['b', 'c']);
console.log(instance.getOrderedPairs()); // => [['b', 'a'], ['c', 'a']]

---

.orderFirst(item)

Orders an item before all other items.

Already established comparisons between the items are immutable.

argument	description
item	The item to order first.

let instance = MaxDiff(['a', 'b', 'c']);
instance.orderFirst('c');
console.log(instance.getOrderedPairs()); // => [['c', 'a'], ['c', 'b']]
instance.orderFirst('b');
console.log(instance.result); // => ['c', 'b', 'a']

---

.orderLast(item)

Orders an item after all other items.

Already established comparisons between the items are immutable.

argument	description
item	The item to order last.

let instance = MaxDiff(['a', 'b', 'c']);
instance.orderLast('a');
console.log(instance.getOrderedPairs()); // => [['b', 'a'], ['c', 'a']]
instance.orderLast('b');
console.log(instance.result); // => ['c', 'b', 'a']

---

.getItemsBefore(item)

Gets all items that are ordered before an item.

The items are ordered by their initial order.

argument	description
item	The item ordered after the items to get.

Returns an array.

let instance = MaxDiff(['a', 'b', 'c', 'd', 'e']);
instance.order('e', 'd', 'a');
instance.order('c', 'a');
console.log(instance.getItemsBefore('a')); // => ['c', 'd', 'e']

---

.getItemsAfter(item)

Gets all items that are ordered after an item.

The items are ordered by their initial order.

argument	description
item	The item ordered before the items to get.

Returns an array.

let instance = MaxDiff(['a', 'b', 'c', 'd', 'e']);
instance.order('e', 'b', 'a');
instance.order('e', 'c');
console.log(instance.getItemsAfter('e')); // => ['a', 'b', 'c']

---

.getUnorderedPairs()

Gets the pairs of the items where the order between the items is unknown.

The items are ordered by their initial order.

Returns an array of arrays.

let instance = MaxDiff(['a', 'b', 'c']);
console.log(instance.getUnorderedPairs()); // => [['a', 'b'], ['a', 'c'], ['b', 'c']]
instance.order('c', 'b');
console.log(instance.getUnorderedPairs()); // => [['a', 'b'], ['a', 'c']]
instance.order('b', 'a');
console.log(instance.getUnorderedPairs()); // => []

---

.getOrderedPairs()

Gets the pairs of the items where the order between the items is known.

The items are ordered by their resulted order.

Returns an array of arrays.

let instance = MaxDiff(['a', 'b', 'c']);
console.log(instance.getOrderedPairs()); // => []
instance.order('c', 'b');
console.log(instance.getOrderedPairs()); // => [['c', 'b']]
instance.order('b', 'a');
console.log(instance.getOrderedPairs()); // => [['b', 'a'], ['c', 'a'], ['c', 'b']]

---

.getUnorderedGroups()

Gets the groups of the items where the order between the items is unknown.

The groups are ordered by their decreasing length. The items are ordered by their initial order.

Returns an array of arrays.

let instance = MaxDiff(['a', 'b', 'c', 'd']);
console.log(instance.getUnorderedGroups()); // => [['a', 'b', 'c', 'd']]
instance.order('d', 'a');
instance.order('b', 'a');
console.log(instance.getUnorderedPairs()); // => [['a', 'c'], ['b', 'c'], ['b', 'd'], ['c', 'd']]
console.log(instance.getUnorderedGroups()); // => [['b', 'c', 'd'], ['a', 'c']]
instance.order('d', 'c', 'b');
console.log(instance.getUnorderedGroups()); // => []

---

.getOrderedGroups()

Gets the groups of the items where the order between the items is known.

The groups are ordered by their decreasing length. The items are ordered by their resulted order.

Returns an array of arrays.

let instance = MaxDiff(['a', 'b', 'c', 'd']);
console.log(instance.getOrderedGroups()); // => []
instance.order('d', 'c', 'b');
instance.order('d', 'a');
console.log(instance.getOrderedPairs()); // => [['c', 'b'], ['d', 'a'], ['d', 'b'], ['d', 'c']]
console.log(instance.getOrderedGroups()); // => [['d', 'c', 'b'], ['d', 'a']]
instance.order('b', 'a');
console.log(instance.getOrderedGroups()); // => [['d', 'c', 'b', a']]

---

.clone()

Clones this instance.

Returns a new instance.