data-transformation-utils

JS Library representing utility allowing assigning a chain of transformations to be executed over input value.

Installation

npm i --save data-transformation-utils

Getting Started

import { Transformer, TwoWayTransformer } from 'data-transformation-utils'

const transformer = new Transformer(transformations)

Examples of usage

Transformer

const transformativeValue = {
  massProp: 1000,
  stringProp: '',
}

const transformationChain = [
  ( object ) => {
    object.massProp = object.massProp / 1000
    return object
  },
  ( object ) => {
    object.stringProp = object.stringProp === '' ? null : object.stringProp
    return object
  }
]


const transformer = new Transformer( transformationChain )

transformer.applyTransformations( transformativeValue )

Result:

{
  massProp: 1,
  stringProp: null
}

const transformativeValue = null

const transformations = [
  ( value ) => value + '13', // always returns string
  ( value ) => {
    return {
      value
    }
  }
]

const transformer = new Transformer( transformations )

const transformedValue = transformer.applyTransformations( transformativeValue, false )

console.log( transformedValue )

Result:

{
  value: "null13"
}

TwoWayTransformer

const transformativeValue = {
  massProp: 1000,
  stringProp: '',
}

const directTransformation = [
  ( object ) => {
    object.massProp = object.massProp / 1000
    return object
  },
  ( object ) => {
    object.stringProp = object.stringProp === '' ? null : object.stringProp
    return object
  }
]

const inverseTransformation = [
  ( object ) => {
    object.massProp = object.massProp * 1000
    return object
  },
  ( object ) => {
    object.stringProp = object.stringProp === null ? '' : object.stringProp
    return object
  }
]

const transformerMods = {}
transformerMods[ TwoWayTransformer.MODS.DIRECT ] = directTransformation
transformerMods[ TwoWayTransformer.MODS.INVERSE ] = inverseTransformation


const transformer = new TwoWayTransformer( transformerMods )

const directTransformedValue = transformer.directTranform( transformativeValue )
const inverseTransformedValue = transformer.inverseTransform( directTransformedValue )

console.log( inverseTransformedValue )

Result:

{
  massProp: 1000,
  stringProp: ""
}

Class Properties

Transformation

constructor( transformationChain )

| Arg | Type | Default | Description | | --- | --- | --- | --- | | transformationChain | array | undefined | transformation function array |

applyTransformations( transformativeValue, keepTypeof )

| Arg | Type | Default | Description | | --- | --- | --- | --- | | transformativeValue | any | undefined | Value to be transformed by the function chain | | keepTypeof | boolean | true | Flag responsible for tracking the returned data type from converter functions |

TwoWayTransformer

static MODS

| property | Description | | --- | --- | | DIRECT | Direct transformation of data | | INVERSE | Inverse transformation |

The sequence of transformation functions in a chain is important

constructor( transformationMods )

| Arg | Type | Default | Description | | --- | --- | --- | --- | | transformationMods | object | undefined | Object of transformation chains corresponding to a particular mod |

Pseudocode:

transformationMods = {
        TwoWayTransformer.MODS.DIRECT: array[],
        TwoWayTransformer.MODS.INVERSE: array[]
}

directTransform( transformativeValue, keepTypeof)

| Arg | Type | Default | Description | | --- | --- | --- | --- | | transformativeValue | any | undefined | Value to be transformed by the function chain | | keepTypeof | boolean | true | Flag responsible for tracking the returned data type from converter functions |

inverseTransform( transformativeValue, keepTypeof)

| Arg | Type | Default | Description | | --- | --- | --- | --- | | transformativeValue | any | undefined | Value to be transformed by the function chain | | keepTypeof | boolean | true | Flag responsible for tracking the returned data type from converter functions |