json-transformer-node/README.md

Json Transformer Utility. Many times you want to interact with 3rd party services or clients, this utility acts as an adaptor and help you mantain code clean by maintaining only the json mappings

### Status
[![Build Status](https://travis-ci.com/Sudhirmiglani/node-json-transformer.svg?branch=master)](https://travis-ci.com/Sudhirmiglani/node-json-transformer)
[![Known Vulnerabilities](https://snyk.io/test/github/Sudhirmiglani/node-json-transformer/badge.svg?targetFile=package.json)](https://snyk.io/test/github/Sudhirmiglani/node-json-transformer?targetFile=package.json)

# json-transformer

A Node.js package that converts json from one format to another.

## Usage

First, install the package using npm:

    npm install json-transformer-node --save

Then, require the package and use it like this:

    var nodeJsonTransformer = require('json-transformer-node');

    var data = {
        x : "xx",
        y : "yy"
    }
    
    var transformation = {
        mapping : {
            item : {
                a : "x",
                b : "y"
            }
        }
    }
    
    var output = nodeJsonTransformer.transform(data, transformation);
    console.log(output);
    
    Output : 
    {
        a : "xx",
        b : "yy"
    }
    
    
## Type of Transformations Supported
    
1. Object to Object Transformation
        
        var data = {
            x : "xx",
            y : {
                z: "zz"
            }
        }
        
        var transformation = {
            mapping : {
                item: {
                    a : "x",
                    b : "y.z" // dot separated path
                }
            }
        }
        
        var output = nodeJsonTransformer.transform(data, transformation);
        console.log(output);
        
        Output : 
        {
            a : "xx",
            b : "zz"
        }
        
2. Array to Array Transformation
            
            var data = {
                x : "xx",
                y : [{
                    z: "z1"
                    },
                    {
                      z: "z2"
                    }]
            }
            
            var transformation = {
                "mapping" :{ 
                    "item":{
                        a : "x",
                        b : [{
                            "list" : "y",
                            "item" : {
                                "c" : "z"
                            }
                        }]
                    }
                }
            }
            
            var output = nodeJsonTransformer.transform(data, transformation);
            console.log(output);
            
            Output : 
            {
                a : "xx",
                b : [{
                        "c" : "z1"
                    },{
                        "c" : "z2"
                    }]
            }

3. Using Hardcoded values
            
            var data = {
                x : "xx",
                y : "yy"
            }
            
            var transformation = {
                "mapping" : {
                    "item":{
                        a : "x",
                        b : "y",
                        c : "$constantValue"
                    }
                }
            }
            
            var output = nodeJsonTransformer.transform(data, transformation);
            console.log(output);
            
            Output : 
            {
                a : "xx",
                b : "yy",
                c : "constantValue"
            }
            
4. Array to Object Transformation
            
            var data = {
                x : {
                    x1 : [{
                            z : "23"
                        },{
                            z : "45"
                        }]
                    },
                y : "yy"
            }
            
            var transformation = {
                            "mapping" : {
                                "item":{
                                    a : {
                                        "flat" : "x.x1#eq(1)",
                                        "item": {
                                            "c" : "z"
                                        }
                                    },
                                    b : "y"
                                }
                            }
                        }
            
            var output = nodeJsonTransformer.transform(data, transformation);
            console.log(output);
            
            Output : 
            {
                a : {
                    c : "45"
                },
                b : "yy"
            }
            
            Note :  "flat" : "x.x1#eq(1)" means flat it, x.x1 is the dot separated path to the array, 
            eq(index) specifies the index to pick
            
5. Object to Array Transformation

            var data = {
                x : {
                    x1 : "123"
                },
                y : 456,
                z : "abc"
            }
            
            var transformation = {
                "mapping" : {
                    "item":{
                       "arrayItems": { 
                            "objectify": "x",
                            "item": { 
                                "car": {
                                    "c1" : "x1",
                                    "c2" : "$abc"
                                }
                             }
                       }
                    }
                }
            }
            
            var output = nodeJsonTransformer.transform(data, transformation);
            console.log(output);
            
            Output : 
            { 
              arrayItems: [{ car: { 
                                    c1: "123", 
                                    c2: "abc" 
                                    }
                          }]
            }
            
6. Type Conversion
            
            var data = {
                x : "123",
                y : 456,
                z : "abc"
            }
            
            var transformation = {
                "mapping" : {
                    "item":{
                        a : "x(NUMBER)",
                        b : "y(STRING)",
                        c : "z(UPPER)"
                    }
                }
            }
            
            var output = nodeJsonTransformer.transform(data, transformation);
            console.log(output);
            
            Output : 
            {
                a : 123,
                b : "456",
                c : "ABC"
            }
            
7. Operations - depends etc.

            var data = {
                x : "RED",
                y : "Jude"
            }
            
            var transformation = {
                "config": {
                    "dependentMap": {
                        "RED": "stop",
                        "GREEN": "go"
                    }
                },
                "mapping" : {
                    "item":{
                        a : "x{DEPENDS}"
                    }
                }
            }
            
            var output = nodeJsonTransformer.transform(data, transformation);
            console.log(output);
            
            Output : 
            {
                a : "stop"
            }
            
## License

Apache 2.0