Persistent ordered mapping from strings
npm install @jimpick/orderedmapPersistent data structure representing an ordered mapping from strings
to values, with some convenient update methods.
This is not an efficient data structure for large maps, just a minimal
helper for cleanly creating and managing small maps in a way that
makes their key order explicit and easy to think about.
License: MIT
The exported value from this module is the class OrderedMap,
instances of which represent a mapping from strings to arbitrary
values.
OrderedMap.from(value: ?Object | OrderedMap) → OrderedMap
Return a map with the given content. If null, create an empty map. If
given an ordered map, return that map itself. If given an object,
create a map from the object's properties.
Instances of OrderedMap have the following methods and properties:
get(key: string) → ?any
Retrieve the value stored under key, or return undefined when
no such key exists.
update(key: string, value: any, newKey: ?string) → OrderedMap
Create a new map by replacing the value of key with a new
value, or adding a binding to the end of the map. If newKey is
given, the key of the binding will be replaced with that key.
remove(key: string) → OrderedMap
Return a map with the given key removed, if it existed.
addToStart(key: string, value: any) → OrderedMap
Add a new key to the start of the map.
addToEnd(key: string, value: any) → OrderedMap
Add a new key to the end of the map.
addBefore(place: string, key: value: string, value: any) → OrderedMap
Add a key after the given key. If place is not found, the new
key is added to the end.
forEach(f: (key: string, value: any))
Call the given function for each key/value pair in the map, in
order.
prepend(map: Object | OrderedMap) → OrderedMap
Create a new map by prepending the keys in this map that don't
appear in map before the keys in map.
append(map: Object | OrderedMap) → OrderedMap
Create a new map by appending the keys in this map that don't
appear in map after the keys in map.
subtract(map: Object | OrderedMap) → OrderedMap
Create a map containing all the keys in this map that don't
appear in map.
size: number
The amount of keys in this map.