@psenger/multivalue-map

# Multi Value Map _ES6 Multi Value Map for NodeJS_ A Multi Value Map is a decorated map, allowing it to have more than one value for a key. Additionally, it has slightly different semantics. Putting a value into the map will add the value to a Array. Getting a value will return an Array, holding all the values put into that key. [![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg)](http://standardjs.com)  ## API  ### Collection Abstract class `Collection` must be implemented to be passed as the `option.valueType` in the MultiValueMap class constructor. This abstract class defines the behavior of the values stored in the MultiValueMap. When constructed, the `creator` parameter, a JavaScript Class, will be called with the `new` operator and stored in a private variable, a reference variable, called `this._proxyObject` #### Parameters * `creator` **Class** the class to construct internally #### setValue Setting the value hides the implementation and off loads the behavior to the Proxy Object.Each backing proxy has different behaviors. ##### Parameters * `value` **any** Passing the value as Null or Undefined are ignored. #### getValue Get the values from the Proxy Object, as a shallow copy array. Returns **[Array][1]\<any>** All sub classes return a shallow copy array of the values #### iterator Iterator ### ArrayCollection **Extends Collection** An Array Collection, is just that, an array. This means there can be duplicated values. #### setValue **Extends Collection** Push a new value into the proxy array object. ##### Parameters * `value` **any** if you push null or undefined, it is ignored. #### getValue **Extends Collection** Gets a shallow copied array of the array of objects. Returns **[Array][1]\<any>** an array of objects. ### SetCollection **Extends Collection** A Set collection enforces uniqueness IFF the values are primitives ( sorry this is JavaScript not Java ). #### setValue **Extends Collection** Add a new Value to the Set. ##### Parameters * `value` **any** if you push null or undefined, it is ignored. #### getValue **Extends Collection** Get an Array ( a shallow copy ) of the values of the Set. Returns **[Array][1]\<any>** All sub classes return an array of the values ### MultiValuedMapOption A MultiValuedMap constructor option Type: [Object][2] #### Properties * `valueType` **[Collection][3]** Indicates the value class and implements the `Collection` ### MultiValuedMap * **See**: [wikipedia][4] for further information on Advanced Data Types * **See**: [wikipedia][5] for further information on MultiMap MultiValuedMap is an ADT ( Advanced Data Type ) and based on Apache Commons Collections. While a Map or Dictionary's keys are associated with a single values, each MultiValueMap's key has multiple values. The cardinality of the values stored can be composed with the property `option.valueType` or building a class that extends the abstract class `Collection`. The default `option.valueType` is an `ArrayCollection`. Type: [MultiValuedMap][6] #### Parameters * `iterable` **Iterable?** An Array or other iterable object whose elements are key-value pairs (arrays with two elements, e.g. \[\[ 1, \['one','two'] ],\[ 2, \['three'] ]]). Each key-value pair is added to the new Map; null values are treated as undefined. * `options` **[MultiValuedMapOption][7]** An option object literal. (optional, default `{}`) * `options.valueType` **[Collection][3]** A decorator, that can be called to supply a value for the collection of values. Optional and defaults to Array (optional, default `{ArrayCollection}`) #### Examples ```javascript const ar = [['a',[1,2,2]],['b',[1,1]]]; const a = new MultiValueMap(); const a = new MultiValueMap( ar ); const a = new MultiValueMap( ar, { valueType: ArrayCollection }); const b = new MultiValueMap( ar, { valueType: SetCollection }); const b = new MultiValueMap( null, { valueType: SetCollection }); ``` **Meta** * **version**: 1.1.1 #### set Sets the value for the key in the Map object. Returns the Map object reference for chaining. ##### Parameters * `key` **any** the key * `value` **any** the value ##### Examples ```javascript const mvm = new MultiValueMap(preData,{ valueType: SetCollection }) mvm.set('D', 'E') ``` Returns **[MultiValuedMap][6]** #### setAll Set All values. ##### Parameters * `key` **any** the key * `values` **Iterable** values to feed. (optional, default `[]`) ##### Examples ```javascript const mvm = new MultiValueMap(preData,{ valueType: SetCollection }) mvm.setAll('F',['G','H','H','H']) ``` Returns **[MultiValuedMap][6]** #### size Returns the number of key/value pairs in the `MultiValueMap` object. ##### Examples ```javascript const mvm = new MultiValueMap(preData,{ valueType: SetCollection }) mvm.set('D', 'E') mvm.set('D', 'E') mvm.set('D', 'E') mvm.setAll('F',['G','H','H','H']) console.log('mvm.size=', mvm.size); // mvm.size= 3 ``` Returns **[number][8]** #### has Returns a boolean asserting whether a value has been associated to the key in the `MultiValueMap` object or not. ##### Parameters * `key` **any** the key ##### Examples ```javascript if ( ! mvm.has('non existing') ) { console.log('not here'); } if ( mvm.has('D') ) { console.log('here'); } ``` Returns **[boolean][9]** indicates a value exists in the MultiValueMap #### delete Returns true if an element in the `MultiValueMap` object existed and has been removed, or false if the element does not exist. It will return false afterwards. ##### Parameters * `key` **any** the key ##### Examples ```javascript if ( ! mvm.delete('A') ) { console.log('A was not deleted'); } ``` Returns **[boolean][9]** true indicates the value was found and deleted #### clear Removes all key/value pairs from the Multi Value Map object. ##### Examples ```javascript mvm.clear() ``` #### keys Returns a new Iterator object that contains an array of \[key, \[value]] for each element in the Map object in insertion order. Returns **IterableIterator\<any>** #### values Return all the values in the Map. Returns **IterableIterator\<any>** An iterable value, composed of what ever values or value was inserted into the map. #### entries The entries in the map, key value pair. ##### Examples ```javascript const data = [ [ 'a', ['1','2','3'] ], [ 'b', ['4'] ], [ 'c', ['5','6'] ] ] const mvn = new MultiValueMap(data); for (let [key, values] of mvn.entries()) { console.log(key, values.getValue()); } // a [ '1', '2', '3' ] // b [ '4' ] // c [ '5', '6' ] ``` Returns **IterableIterator<\[any, IterableIterator\<any>]>** #### get get the values associated with the key. ##### Parameters * `key` **any** The key ##### Examples ```javascript const mvm = new MultiValueMap([iterable]) mvm.set('Captain Marvel', 'Carol Danvers') const value = mvm.get('Captain Marvel') console.log( value ) // ['Carol Danvers'] ``` Returns **(any | null)** [1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array [2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object [3]: #collection [4]: https://en.wikipedia.org/wiki/Abstract_data_type [5]: https://en.wikipedia.org/wiki/Multimap [6]: #multivaluedmap [7]: #multivaluedmapoption [8]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number [9]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean   ## Example Usage ```javascript const preData = [['A',['B','B','C']]] const mvm = new MultiValueMap(preData,{ valueType: SetCollection }) mvm.set('D', 'E') mvm.set('D', 'E') const value = mvm.get('A') console.log( value ) // [ 'B', 'C' ] for (let [key, values] of mvm.entries()) { console.log(key, values.getValue()); } // A [ 'B', 'C' ] // D [ 'E' ] ```   ## Installation Instructions ```bash npm install @psenger/multivalue-map --save ``` or ```bash yarn add @psenger/multivalue-map ```  ## License  MIT License Copyright (c) 2021 Philip A Senger 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.  ## Deployment Steps * create a pull request from `dev` to `main` * check out `main` * `npm version patch -m "message here" or minor` * `npm publish --access public` * Then switch to `dev` branch * Then merge `main` into `dev` and push `dev` to origin