json-map-transform
A lighweight Node library that transforms a json object or an array of json objects based on tranformation template.
Installation
Using npm:
npm i --save json-map-transform
Usage
Template
Key: Each key property in the template object describes the path to the property in the output object. This is where the value in path of the input object will be mapped to.
Path: Is the path to the property in the input object that will be mapped to the template key. It can also be an array of possible paths in case the objects doesn't follow an exact pattern.
Transform: Is a callback that can be used to transform the current property. It receives two parameters: (property, originalObject).
Default: In case a path does not exists in the input object or the value returned by transform is undefined, the default value will be used.
OmitValues: Sometimes it is necessary to ignore values on the transformation (ex: undefined, empty string or other values depending on a business rule). With the omitValues, it is possible to define an array of values that should be ignored on the transformation. The output object will not have the associated key.
Template example:
const template = title: path: 'name' val label: path: 'category' 'categories' omitValues: '' undefined 'ERROR' vendor: path: 'meta.vendor' default: 'No vendor' 'meta.photos': path: 'photos' val 'meta.id': path: 'code' This template will work like this:
| from | to | transform |
|---|---|---|
| name | title | toUpperCase() |
| [category, categories] | label | |
| meta.vendor | vendor | |
| photos | meta.photos | photo.photoUrl |
| code | meta.code |
Single object transformation
const transform = ; //The json objects to be transformedconst product1 = name: 'Hello world' code: 'BOOK01' category: 'books' price: '200' photos: title: 'photo1' photoUrl: 'http://photo1.jpg' isCover: true title: 'photo2' photoUrl: 'http://photo2.jpg' meta: vendor: 'Author name' ; const product2 = name: 'My Digital Product' code: 'DIGITAL01' category: 'digital' price: '500' photos: title: 'photo3' photoUrl: 'http://photo3.jpg' isCover: true title: 'photo4' photoUrl: 'http://photo4.jpg' meta: vendor: 'Global Digital' ; convertedJson = ; //Output object "title": "HELLO WORLD" "label": "books" "vendor": "Author name" "meta": "photos": "http://photo1.jpg" "http://photo2.jpg" "id": "BOOK01" You ca also use an optional callback to be executed after the transformation
const afterTransform = Object; ; // Output json "title": "HELLO WORLD" "label": "books" "vendor": "Author name" "meta": "photos": "http://photo1.jpg" "http://photo2.jpg" "id": "BOOK01" "categoryCode": 101Array transformation
// The afterTransform callback is also optional; "title": "HELLO WORLD" "label": "books" "vendor": "Author name" "meta": "photos": "http://photo1.jpg" "http://photo2.jpg" "id": "BOOK01" "categoryCode": 101 "title": "MY DIGITAL PRODUCT" "label": "digital" "vendor": "Global Digital" "meta": "photos": "http://photo3.jpg" "http://photo4.jpg" "id": "DIGITAL01" "categoryCode": 102 The afterTransform callback is called after each element tranformation.