https://github.com/bimedia-fr/bimedia-objectmapper

object mapper for node
https://github.com/bimedia-fr/bimedia-objectmapper

Last synced: 8 days ago
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object mapper for node

• Host: GitHub
• URL: https://github.com/bimedia-fr/bimedia-objectmapper
• Owner: bimedia-fr
• License: apache-2.0
• Created: 2014-03-03T11:22:21.000Z (almost 11 years ago)
• Default Branch: master
• Last Pushed: 2022-08-25T14:10:56.000Z (over 2 years ago)
• Last Synced: 2024-12-17T08:14:18.655Z (19 days ago)
• Language: JavaScript
• Size: 50.8 KB
• Stars: 0
• Watchers: 11
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
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==================

object mapper for node

Object Mapper Module

-----------------

This module allow to map keys and values from an object to an other. Mapping uses a tranformation rules. 

There are 3 transformation rules types : 

* *identity* : copy the attribute and value to the target object.

* *alias* : rename the attribute in the target object (value is unchanged).

* *complex* : apply tranformation rule provided to change attribute name and value.

### Installation

`npm install --save bimedia-objectmapper`

### Usage

#### Simple usecase

```javascript

var ObjectMapper = require('bimedia-objectmapper');

var mapper = objectMapper({'key':'clé'});

var result = mapper({key:'value'});

// {'clé': 'value'}

```

#### Streams

```javascript

var objectMapper = require('bimedia-objectmapper'), 

  fs = require('fs'), 

  JSONStream = require('JSONStream');

  

var mapper = objectMapper(rules);

fs.createReadStream('package.json')

  .pipe(JSONStream.parse())

  .pipe(mapper.stream())

  .pipe(process.stdout);

```

#### Arrays

```javascript

var objectMapper = require('bimedia-objectmapper');

var mapper = objectMapper({'key':'clé'});

var sources = [{key:'value1'}, {key:'value2'}, {key:'value3'}];

var result = sources.map(mapper);

//[ { 'clé': 'value1' },

//  { 'clé': 'value2' },

//  { 'clé': 'value3' } ]

```

### Mapping rules definitions

#### Identity Rule

No specific rule is needed. Attribute is copied to target object.

#### Simple Rule (alias) 

Declare a constant as attribute value. Example :

```javascript

var rules = {

    "trxpvptpv": "trxid"

};

```

This rule renames *trxpvptpv* attribute in source object, to *trxid*

in target object. 

#### Complex Rule

Define an object matching the source attribute. 

Example :

```javascript

var rules = {

     'state' : {

        name : 'currentState',

        mapper : function (val) {

            if (val == 'Y') {

                return 'REFUNDED';

            }

            return val == 'N' ? 'REFUSED' : 'PENDING';

        }

    }

};

```

Or directly with a function :

```javascript

var rules = {

     'state' : function (k, v) {

            var value;

            if (val == 'Y') {

                value =  'REFUNDED';

            }

            value = val == 'N' ? 'REFUSED' : 'PENDING';

            return {key: 'currentState', value: value};

        }

    }

};

```

This 2 examples transforms the *state* attribute in source object to an *currentState*

attribute in target object.

### Options

Mapping can be customize with the second argmuent of `ObjectMapper` :

For instance to disable identity mapping by default :

```js

var mapper = ObjectMapper(rules, {defaults: false});

```

Or to specify a default mapping function :

```js

var mapper = ObjectMapper(rules, {defaults: ObjectMapper.keys.camelCase});

```

#### supported options

* `defaults` : (function | boolean) define a default mapping function. By defaut `ObjectMapper.identity`.