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
default usage
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
}Ignore changing the data type in the transformation functions
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:
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 |