JSON-Reform

A mini NodeJS library that helps you transform JSON objects faster & easier.

Installation

Using NPM:

npm install json-reform

In browser:

<script src="reform.js"></script>

Usage

const re = new Reformer(rules [,opts])

Transformation Rules

rules is an object whose keys are names of attributes that you want to transform, values define how these attribute will be transformed.

There are multiple ways to define them:

Rename an attribute

{
  old_name: "new_name"
}

Do something with the value

{
  version: function(v){
      return v+1;
  }
}

Full definition

{
  version: {
      name: 'ver',
      handler: function(v){
          return v+1;
      }
  }
}

One to many relationship

Attribute a will be transformed to a, b and c in the new object.

{
  a: [
      // this produces a
      function(val){
        return val-1;
      },
      
      // this produces b
      "b",
      
      // this produces c
      {
        name: "c",
        handler: function(old_value){
            return old_value + 1;
        }
      }]
}

Many to one relationship

You can access other attribute with the second parameter in the handler function.

{
  x: {
      name: 'z',
      handler: function(x, obj){
          const y = obj.y;
          return x+y;
      }
  }
}

Options

Name|Type|Default|Description :-----------|:------|:----|:----------- keepUnlisted|Boolean|false|Attributes of origin object that are not listed in schema will be kept. async |Boolean|false|transform() function will return a Promise. This option must be set to true when you are using any asynchronous function sequential |Boolean|false|When an array of objects is passed to transform() function, those will be transformed one after another. This may help to avoid overhead when you are sending network requests.

Example

const Reformer = require('json-reform');

const re = new Reformer({
    a: "b",
    c: {
        name: "d",
        handler(val, obj) {
            return val + 1;
        }
    },
    d: [{
        name: "e",
        handler(val) {
            return val + 1;
        }
    }, {
        name: "f",
        handler(val) {
            return val + 2;
        }
    }]
}, {keepUnlisted: true});

const result = re.transform({a: 1, b: 2, c: 3, d: 5, g: 0});
console.log(result);

Output:

{ f: 7, e: 6, d: 4, b: 2, g: 0 }

You can also transform an array of objects

const result = re.transform([{a: 1, b: 2, c: 3, d: 5, g: 0}]);

Output:

[
    { f: 7, e: 6, d: 4, b: 2, g: 0 }
]

When async option is true:

re.transform([{a: 1, b: 2, c: 3, d: 5, g: 0}])
    .then(res => {
        // Do something
    })

License

MIT © Thien Phuc Tran