@browndragon/collections

A collection of es6-like datastructures I wanted to use and didn't find an equivalent quickly enough in npm.

EmptyIter

A quick iteratable & iterator that contains nothing. I'm not sure if you usually return function*(){}() but since I wanted to cache the entry anyway...

MultiMap

A Map<K, Set<V>> (... more or less...).

From an insertion point of view, you add(k,v) (instead of set(k,v)), and multiple adds don't result in overwriting the value of k. map.get(k) returns an iterator of values. Iterators conceive of the entries as pairs [k, v] for nonunique k.

SortedMap and SortedSet

These types assume "phased" interactions -- a flurry of modifications followed by a flurry of reads or iterations, followed by a flurry of modifications etc. As a result, they cache an iteration order (via sorted array) calculated whenever an iteration follows a dirtying operation.

Anyway; they change the es6 guaranteed sorting order from "insertion order" to "natural sorting order". You can modify this with FooClass.comparing((a, b)=> 0 /* or -1 or +1, as appropriate */) -- which returns a new subclass.

Ranges

The iteration methods (entries, keys, values, etc) generally accept optional parameters begin and end (so: someMap.entries(begin, end)). Undefined limits nothing; the first iterated element will be equal to or greater than begin, the last iterated element will be strictly less than end.

Table

A 2-d Map; you can think of it a little bit as a Map<[Krow, Kcol], V>.

From an insertion point of view, you set(row, col, val). From an iteration point of view, you iterate over [[row, col], val] -- and the constructor's iterator argument expects the values to be bunched in this fashion.

Additional methods are provided to use the row-based (or without loss of generality, column-based) view of the data as restricted by some of the keys.

The Table itself has a native iteration order (as Map, the order of entries created). However, using various index restrictions, you will get the iteration order of the index type -- rows can be thought of as a map of columns->values, and columns a map of rows->values; the constructor accepts an additional 2 parameters to use other map implementations (SortedMap, for instance).

Usage

import collections from '@browndragon/collections';

// TODO: DEMONSTRATE API