Short key generator

Why?

To reduce size of JSON with a large data set that is transmitted over the network. I've seen this in quite a few projects - always done from scratch and usually not very well.

Problem

var toSend = {
  data: [
    {
      selfExplanatoryKey1: 11,
      selfExplanatoryKey2: 22,
      ...
      selfExplanatoryKeyN: 997
    },
    {
      selfExplanatoryKey1: 66,
      selfExplanatoryKey2: 77,
      ...
    },
  ]
};

The stringified JSON gets very large because of the long self-explanatory keys.

Solution

var toSend = {
  data: [
    {
      A: 11,
      B: 22,
      ...
      Cm: 997
    },
    {
      A: 66,
      B: 77,
      ...
    },
  ],
  map: {
    selfExplanatoryKey1: 'A',
    selfExplanatoryKey2: 'B',
    ....
    selfExplanatoryKeyN: 'Cm'
  }
};

Basic Usage

var keyMapFactory = require('short-key-generator');
var keyMap = keyMapFactory();
keyMap.getOrCreate('selfExplanatoryKey1'); // 'A'
keyMap.getOrCreate('selfExplanatoryKey2'); // 'B'
keyMap.getOrCreate('selfExplanatoryKey1'); // 'A'

// map object keys and keep the values unchanged
keyMap.mapObjectKeys({
  selfExplanatoryKey2: 1,
  selfExplanatoryKey3: {selfExplanatoryKey4: 2}
}); // {'B': 1, 'C': {selfExplanatoryKey4: 2}}

keyMap.getMap();
// returns
//  {
//    selfExplanatoryKey1: 'A',
//    selfExplanatoryKey2: 'B',
//    selfExplanatoryKey3: 'C'
//  }

// if you need inverted map like {A: 'selfExplanatoryKey1'}, use
keyMap.getIvertedMap();

API Reference

The default export of this module is ~keyMap(). That and probably ~characterRange() are the only things you need. The other module members (classes) are exported just in case you feel like you want to extend them and it is not worth a pull request.

• short-key-generator
  • ~KeyMap
    • .getOrCreate(longKey) ⇒ string
    • .getKey(longKey) ⇒ string | undefined
    • .mapObjectKeys(obj) ⇒ Object
    • .getMap() ⇒ Object
    • .getInvertedMap() ⇒ Object
  • ~SequentialKeyGen
    • .getNextKey() ⇒ string
  • ~characterRange(firstChar, lastChar, optStep) ⇒ Array.<string>
  • ~keyMap() ⇒ KeyMap
  • ~sequentialKeyGen() ⇒ SequentialKeyGen

~~KeyMap

Kind: inner class of short-key-generator

• ~KeyMap
  • .getOrCreate(longKey) ⇒ string
  • .getKey(longKey) ⇒ string | undefined
  • .mapObjectKeys(obj) ⇒ Object
  • .getMap() ⇒ Object
  • .getInvertedMap() ⇒ Object

keyMap.getOrCreate(longKey) ⇒ string

Get an existing short key for provided long key. If it doesn't exist, new short key is created

Kind: instance method of KeyMap

| Param | Type | | --- | --- | | longKey | string |

keyMap.getKey(longKey) ⇒ string | undefined

Get an existing short key for provided long key

Kind: instance method of KeyMap
Returns: string | undefined - undefined if there is no entry for longKey

| Param | Type | | --- | --- | | longKey | string |

keyMap.mapObjectKeys(obj) ⇒ Object

Utility method to rename object keys

Kind: instance method of KeyMap
Returns: Object - new object with original values

| Param | Type | | --- | --- | | obj | Object |

keyMap.getMap() ⇒ Object

Kind: instance method of KeyMap
Returns: Object - map of all entries: {longKey: shortKey}

keyMap.getInvertedMap() ⇒ Object

Kind: instance method of KeyMap
Returns: Object - map of all entries: {shortKey: longKey}

~~SequentialKeyGen

Kind: inner class of short-key-generator

sequentialKeyGen.getNextKey() ⇒ string

Generate new key

Kind: instance method of SequentialKeyGen

~~characterRange(firstChar, lastChar, optStep) ⇒ Array.<string>

Utility function to create a range/array of characters

Kind: inner method of short-key-generator
Returns: Array.<string> - array of characters

| Param | Type | Description | | --- | --- | --- | | firstChar | string | first character of the desired range - first character of the provided string is used - non-strings are coverted to string - if no character (empty string) is provided, empty array is returned | | lastChar | string | last character of the desired range; same behavior as firstChar | | optStep | string | step - default is one, decimals are floored, 0 converted to 1 |

~~keyMap() ⇒ KeyMap

Function creating new instance of KeyMap

Kind: inner method of short-key-generator

| Param | Type | Default | Description | | --- | --- | --- | --- | | [options.initInvertedMap] | Object.<string, string> | Object() | initialize map, e.g. {shortKey: 'longKey'} | | [options.alphabet] | Array.<string> | ['A'-'Z'] | strings used to generate new keys | | [options.initCounter] | number | 0 | use if you want to skip a few keys at the beginning | | [options.glueFn] | function | fragments => fragments.join('') | keys are created with one or more strings from the alphabet. By default, they are combined with .join('') |

~~sequentialKeyGen() ⇒ SequentialKeyGen

Function creating new instance of SequentialKeyGen Exported as member sequentialKeyGen

Kind: inner method of short-key-generator

| Param | Type | Default | Description | | --- | --- | --- | --- | | [options.alphabet] | Array.<string> | ['A'-'Z'] | strings used to generate new keys | | [options.initCounter] | number | 0 | use if you want to skip a few keys at the beginning | | [options.glueFn] | function | fragments => fragments.join('') | keys are created with one or more strings from the alphabet. By default, they are combined with .join('') |

Contributing

Feel free to suggest new features or create pull requests (PR). With PR, keep the test coverage at 100% ;)

Clone the repo and develop new feature or bug fix

$ git clone https://github.com/stropho/short-key-generator.git
$ cd short-key-generator
$ npm i
$ npm run test:unit:watch

Tests autamatically run on change in src/ or test/ folder.

To run other tasks like linter, coverage or build, simply run

$ npm run all

Basic concept

• JavaScript ES6
• ES6 Transpiler
  • babel
• Build system
  • gulp
• Test framework
  • mocha
  • istanbul & nyc
• Code style
  • idiomatic
  • eslint (using JS code style idiomatic)

Script Tasks

build

Build the code from ./src, store in ./dist

$ npm run build

Test

## Unit tests
$ npm run test:unit

## All tests and linter for test files
$ npm run test

Test coverage

$ npm run coverage

Linting

## Lint `./src`
$ npm run lint

## Lint './test`
$ npm run lint:test