json2json-transformer

Transform a generic object using JSONPath.

Pulls data from a data object using JSONPath and generate a new objects based on a template. Each of the template's properties can pull properties from the source data or an array of all results found by its JSONPath. When pulling an array of data you can also supply a subtemplate to transform each item in the array.

Import

Import in your project using

npm i --s json2json-transformer

Usage

Import reference in javascript

const render = require('json2json-transformer');

Import reference in typescript

import * as render from 'json2json-transformer'

Define a template

let template = {
    literalProperty: "Constant",                                                                        // Constant string in template
    "'$.propertyName'": "Constant 2",                                                                   // Change property name at step3
    simpleProperty : "'$.propertyDemo1'",                                                               // Dynamic property (first level in data obj)
    composeProperty : "Two strings '$.propertyDemo1''$.propertyDemo2' and a number '$.mumberValue'",    // Computed propery thet mix strings and number
    deepProperty : "'$.complexObject.nestedProperty'",                                                  // Dynamic property (second level in data obj)
    complexObject : {                                                                                   // Complex object in template
        nestedProperty: "'$.data2' valorized with other data",                                          // This property is not present in first data obj
        "'$.nestedPropertyName'": "'$.data2' valorized with other data"                                 // Change nested property name and value at step3
    },
    arrayProperty: [                                                                                    // Static array defined in template
        "literal in array",                                                                             // Static literal string in array
        "'$.stringInArray'",                                                                            // Dynamic string in array
        {                                                                                               
            ObjectInArray: "'$.inArray'"                                                                // Dynamic property inside an object in array
        }
    ],
    "'$..values'":                                                                                      // Dynamic array in template, path in data source
    ["repeatedTemplate",                                                                                // Property name in destination object
    {                                 
        repeatedSimpleProp:"'$.val'"                                                                    // Array item template
    }]
}

Define object data

var data1 = {
    propertyDemo1: "some value",
    propertyDemo2: "other value",
    complexObject: {
        nestedProperty: "deep"
    },
    inArray: "Inside an object in array!",
    stringInArray: "Inside an object in array!",
    mumberValue:5000,
}
 
var data2 = {
    data2: "more data",
    values:[{
        val: 0
    }]
}
 
var data3 = {
    propertyName: "A property",
    nestedPropertyName: "Nested Property Name"
}

Apply template

// Apply data1 at template object. All un matched properties will be ignored
let step1 = render.parseTemplate(data1, template, { clone: true });
 
// Apply data2 at step1 output. All un matched properties will be ignored
let step2 = render.parseTemplate(data2, step1, { clone: true });
 
let step3 = render.parseTemplate(data3, step2, {
    clone: true,
    transformProps: (s) => s.replace(/ /g, "-").toLowerCase()
});
 
// Print output in console
console.log("template", JSON.stringify(template, null, 2));
console.log("step1", JSON.stringify(step1, null, 2));
console.log("step2", JSON.stringify(step2, null, 2));
console.log("step3", JSON.stringify(step3, null, 2));