IndexedMap

An enhanced map that supports easy insertion or deletion at specific position. Give access to entries by index or key. Can be used instead of a linked list.

Stability: 4 - API Frozen

( see Stability Index )

Install

as node module with npm:

npm install indexed-map --production

Usage

Can be used as node module 'indexed-map', as AMD module 'indexed-map' or as global class at window.IndexedMap.

var IndexedMap = require('indexed-map');
var myMap = IndexedMap();
// add an entry at the end
myMap.insert('myKey', { myProperty:'My Value' });

Keys have to be of type 'string' and unique in map. Values can by any type, there is no restrictions.

Some methods supported in two versions, one with key as reference and the other works with index as reference (has suffix 'At').

Constructor

• var myMap = IndexedMap();
• var myMap = new IndexedMap();

Keyword new is optional, it will be called by IndexedMap itself, if necessary.

properties

• length {number} the count of entries

• keys {Array} keys in the current order

  It is the real keys array of the indexedMap, not a clone. So do not add, change or remove elements. That would result in an inconsistent state of indexedMap itself.

  The advantage of not cloning the key map is, that you can easily manipulate the order of keys, if you like. So you could use the reverse or sort method of Array.

has, get, insert, set, move, remove

• has( key:string ):boolean

  checks, if given key is in map.

  return {boolean} true, if it could found otherwise false

• get( key:string ) : value|null

• getAt( index:number ) : value|null

  return Value for given key/index or null, if key was not found.

• getFirst():value|null

• getLast():value|null

  return Value of first/last entry or null, if map is empty.

• insert( key:string, value:any ):value|null

• insertAt( index:number, value:any ):value|null

  Insert new element before the referenced element targetKey. If reference is null or not found, new element is inserted at the end of the list.

  return Value for key or null if !key or key always used.

• set( key:string, value:any ) : oldValue|null

• setAt( index:number, value:any ) : oldValue|null

  Overwrite the value for the given key/index.

  return The old value or null, if key/index not found.

• move( key:string, targetKey:string ) : value|null

• moveAt( index:number, targetIndex:number ) : value|null

  Move the key to position of targetKey by inserting key before targetKey. If targetKey is not found, key will be moved to the end.

  return Value for key or null if key was not found.

• remove( key:string ) : oldValue|null

• removeAt( index:number ) : oldValue|null

  Remove the entry for the given key.

  return The old value or null, if key was not found.

next, previous

The IndexedMap do not have a current element. To get next or previous entry, you need to give a reference entry to the function.

• nextKeyOf( key:string ) : key|null

• prevKeyOf( key:string ) : key|null

  return key from entry next/previous to given key or null, if key has no next/previous.

• getNextOf( key:string ) : value|null

• getPrevOf( key:string ) : value|null

  return Value from entry next/previous to given key or null, if key has no next/previous.

iterating methods

• sort( [callback] )

  Sort the map, that method manipulate the indexedMap. This function is analog to the sort function of Array. if no callback is specified, keys will be sorted lexicographically

  params callback {function(this:IndexedMap, valueA:any, valueB:any):number} - optional

  • called in context of indexedMap
  • compareFunction have to return 0 for equal, <0 for a < b or >0 for a > b

  return The indexedMap

• find(callback [, startIndex])

  Returns the first key, where callback function returns true.

  param {function(this:IndexedMap, key:string, value:any):boolean} callback - required

  • called for every entry in context of indexedMap
  • return true will stop the search and return the value of current visited entry.

  param {number} startIndex - optional Position to start the search, default is 0.

  return Value of first entry found or null, if nothing found

• each(callback [, startIndex])

  Iterate over the indexedMap. Start at given startIndex. Run until end or the given callback returns 'false'.

  param {function(this:IndexedMap, key:string, value:any):boolean} callback - required

  • called for every entry in context of current IndexedMap
  • stop loop from within the callback function by returning false

  param {number} startIndex - optional position to start the run, default: 0

  return Zhe indexedMap or null for error (missing callback).

Test

cd <IndexedMapDir>
npm install .
npm test

License

The MIT License

Copyright (c) 2012-2013 Tobias Lindig

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.