json-mapper

v0.0.12

Published

3 years ago

simple json mapper to

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dregenor

json map mapper transform transformation json to json converter

json-mapper

Just a simple json mapper.

How to use

Very simple case:


var input = {
    user: {
        name: 'John',
        nick: 'C00lHacker'
    }
};

var JM = require('json-mapper');

var converter = JM.makeConverter({
    name: function(input){
            if (!input.user){
                return;
            } else {
                return input.user.name;
            }
    }
});

var result = converter(input);

console.log(result); // should be {name: 'John'}

Let's add a bit sugar by using factory method getVal


var converter = JM.makeConverter({
    name: JV.getVal('user.name');
});

The syntax 'user.name' equals JM.getVal('user.name')


var converter = JM.makeConverter({
    name: 'user.name';
});

If you want to chain callbacks use ch factory


var input = {
  user: {
      name: 'Alex',
      nickname: 'FOfan'
  },
  locations: [
      {x:1, y:21}, // i need this x
      {x:2, y:22},
      {x:3, y:23},
      {x:4, y:24},
      {x:5, y:25},
      {x:6, y:26},
      {x:7, y:27},
      {x:8, y:28},
      {x:9, y:29},
      {x:10, y:30},
      {x:11, y:31},
      {x:12, y:32}
  ],
  uuid: 'ffffffff-aaaaaaaa-c0c0afafc1c1fefe0-cfcf1234'
};


var JM = require('json-mapper');
var converter = JM.makeConverter({
    val: JM.ch(
                function(input){ return input.locations; },
                function(input){ return input[0]; },
                function(input){ return input.x; }
            )
});

var result = converter(input); // should be {val: 1}

This stuff can be simplified by using array, e.g.:


var input = {
  user: {
      name: 'Alex',
      nickname: 'FOfan'
  },
  locations: [
      {x:1, y:21}, // i need this x
      {x:2, y:22},
      {x:3, y:23},
      {x:4, y:24},
      {x:5, y:25},
      {x:6, y:26},
      {x:7, y:27},
      {x:8, y:28},
      {x:9, y:29},
      {x:10, y:30},
      {x:11, y:31},
      {x:12, y:32}
  ],
  uuid: 'ffffffff-aaaaaaaa-c0c0afafc1c1fefe0-cfcf1234'
};


var JM = require('json-mapper');

var converter = JM.makeConverter({
    val: [
        function(input){ return input.locations; },
        function(input){ return input[0]; },
        function(input){ return input.x; }
    ]
});

var result = converter(input); // should be {val: 1}

JM.ch function also can convert 'some.path' to JM.getVal('some.path').
There is a map factory for arrays processing.


var input = {
    user: {
        name: 'Alex',
        nickname: 'FOfan'
    },
    locations: [
        {x:1, y:21}, // i need this x
        {x:2, y:22},
        {x:3, y:23},
        {x:4, y:24},
        {x:5, y:25},
        {x:6, y:26},
        {x:7, y:27},
        {x:8, y:28},
        {x:9, y:29},
        {x:10, y:30},
        {x:11, y:31},
        {x:12, y:32}
    ],
    uuid: 'ffffffff-aaaaaaaa-c0c0afafc1c1fefe0-cfcf1234'
};


var JM = require('json-mapper');

var converter = JM.makeConverter({
    val: JM.ch('locations', JM.map(function(input){ return input.x; }))
});

var result = converter(input); // should be {val: [1,2,3,4,5,6,7,8,9,10,11,12]}


var converter = JM.makeConverter({
    val: ['locations', JM.map('x')]
});

Use JM.makeCb(val) to convert path to getVal

Returning map:

New feature is '$root' alias


var JM = require('json-mapper');

var input = {
    uuid: '1233123123',
    user: {
        name: 'sergey'
    },
    objects: [
        'atoken',
        'btoken',
        'ctoken',
        'dtoken',
        'etoken',
        'Fplane',
        'Splane',
        'nodejs',
        'memcache',
        'sql',
        'tpl',
        'ej'
    ]
};

var converter = JM.makeConverter({
    originalObject: '$root',
    uuid: 'uuid',
    link: [
        JM.helpers.templateStrong('http://127.0.0.1/users/?name={user.name}'),
        JM.helpers.templateStrong('<a href="{$root}">user</a>')
    ],
    objects: ['objects', JM.map(JM.helpers.templateStrong('http://127.0.0.1/objects/{$root}'))]
});

console.log('\n\n\n\ convert with template & root', converter(input));

Result:


{
    originalObject: {
        uuid: '1233123123',
        user: {name: 'sergey'},
        objects: [
            'atoken',
            'btoken',
            'ctoken',
            'dtoken',
            'etoken',
            'Fplane',
            'Splane',
            'nodejs',
            'memcache',
            'sql',
            'tpl',
            'ejs'
        ]
    },
    uuid: '1233123123',
    link: '<a href="http://127.0.0.1/users/?name=sergey">user</a>',
    objects: [
        'http://127.0.0.1/objects/atoken',
        'http://127.0.0.1/objects/btoken',
        'http://127.0.0.1/objects/ctoken',
        'http://127.0.0.1/objects/dtoken',
        'http://127.0.0.1/objects/etoken',
        'http://127.0.0.1/objects/Fplane',
        'http://127.0.0.1/objects/Splane',
        'http://127.0.0.1/objects/nodejs',
        'http://127.0.0.1/objects/memcache',
        'http://127.0.0.1/objects/sql',
        'http://127.0.0.1/objects/tpl',
        'http://127.0.0.1/objects/ejs'
    ]
}

Shut up and show me a SIMPLE convertion


var input = {
  user: {
      name: 'Alex',
      nickname: 'FOfan'
  },
  locations: [
      {x:1, y:21}, // i need this x
      {x:2, y:22},
      {x:3, y:23},
      {x:4, y:24},
      {x:5, y:25},
      {x:6, y:26},
      {x:7, y:27},
      {x:8, y:28},
      {x:9, y:29},
      {x:10, y:30},
      {x:11, y:31},
      {x:12, y:32}
  ],
  uuid: 'ffffffff-aaaaaaaa-c0c0afafc1c1fefe0-cfcf1234'
};


var JM = require('json-mapper');
var converter = JM.makeConverter({
    all_x: ['locations', JM.map('x')],
    all_y: ['locations', JM.map('y')],
    x_sum_y: ['locations', JM.map(function(input){
        return input.x + input.y;
    })],
    locations_count: ['locations', function(arr){
        return arr.length;
    }],
    locations_count_hack: 'locations.length',
    just_mappet_name: 'user.name',
    another_object: {
        nickname: 'user.nickname',
        location_0_x: 'locations.0.x'
    }
});

var result = converter(input);

console.log(result);

Result:


{
  "all_x":   [ 1,  2,  3,  4,  5,  6,  7,  8,  9,  10, 11, 12 ],
  "all_y":   [ 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32 ],
  "x_sum_y": [ 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 ],
  "locations_count": 12,
  "locations_count_hack": 12,
  "just_mappet_name": "Alex",
  "another_object": {
    "nickname": "FOfan",
    "location_0_x": 1
  }
}

Helpers

template and templateStrong

Just an example:


var JM = require('json-mapper');

var input = {
    uuid: '1233123123',
    user: {
        name: 'sergey'
    },
    objects: [
        {id: 1001, name: 'atoken'},
        {id: 1002, name: 'btoken'},
        {id: 1003, name: 'ctoken'},
        {id: 1004, name: 'dtoken'},
        {id: 1005, name: 'etoken'},
        {id: 1006, name: 'Fplane'},
        {id: 1007, name: 'Splane'},
        {id: 1008, name: 'nodejs'},
        {id: 1009, name: 'memcache'},
        {id: 1010, name: 'sql'},
        {id: 1011, name: 'tpl'},
        {id: 1012, name: 'ej'}
    ]
};


var converter = JM.makeConverter({
    uuid:           'uuid',
    hrefStrong:     JM.helpers.templateStrong('http://127.0.0.1/users/?name={user.name}'),
    href:           JM.helpers.template('http://127.0.0.1/users/?name={user.name}'),
    hrefStrongFail: JM.helpers.templateStrong('http://127.0.0.1/users/?name={user.undefinedKey}'),
    hreffail:       JM.helpers.template('http://127.0.0.1/users/?name={user.undefinedKey}'),
    objects: ['objects', JM.map({
        href: JM.helpers.templateStrong('http://127.0.0.1/objects/{id}')
    })]
});

console.log('\n\n\n convert with template \n\n', converter(input));

Result:


{
    uuid:        '1233123123',
    hrefStrong:  'http://127.0.0.1/users/?name=sergey',
    href:        'http://127.0.0.1/users/?name=sergey',
    hreffail:    'http://127.0.0.1/users/?name=undefined',
    objects: [
        { href: 'http://127.0.0.1/objects/1001' },
        { href: 'http://127.0.0.1/objects/1002' },
        { href: 'http://127.0.0.1/objects/1003' },
        { href: 'http://127.0.0.1/objects/1004' },
        { href: 'http://127.0.0.1/objects/1005' },
        { href: 'http://127.0.0.1/objects/1006' },
        { href: 'http://127.0.0.1/objects/1007' },
        { href: 'http://127.0.0.1/objects/1008' },
        { href: 'http://127.0.0.1/objects/1009' },
        { href: 'http://127.0.0.1/objects/1010' },
        { href: 'http://127.0.0.1/objects/1011' },
        { href: 'http://127.0.0.1/objects/1012' }
    ]
}

templateStrong will return undefined if there is undefined keys

def


var JM = require('json-mapper');

var converter = JM.makeConverter({
    uuid: JM.helpers.def('14')
});

console.log('\n\n\n convert with default \n\n', converter({}));

Result:


{
    uuid: '14'
}

JM.helpers.def(val) - always returns val

valOrDef


var JM = require('json-mapper');

var converter = JM.makeConverter({
    uuid:  [ 'uuid' , JM.helpers.def('14') ],
    uuid2: [ 'uuid2', JM.helpers.valOrDef('15') ]
});

console.log('\n\n\n convert with default \n\n', converter({
    'uuid': '15',
    'uuid2': '17'
}));

Result:


{
    uuid: '14',
    uuid2: '17'
}

If input is null or undefined JM.helpers.valOrDef(val) will return val, otherwise input will be returned.

dict


var JM = require('json-mapper');

var converter = JM.makeConverter({
    type: [
        'type' ,
        JM.helpers.dict({
            1: 'fit',
            2: 'crop',
            3: 'fit'
        })
    ]
});

console.log('\n\n\n convert with default \n\n', converter({
    'type': 1
}));

Result:


{
    type: 'fit'
}

toBoolean, toNumber, toString, toUndefined, filterUndefined


var JM = require('json-mapper');
var h = JM.helpers;

var converter = JM.makeConverter({
    isGuest: ['role', h.toBoolean],
    isUser: ['user', h.toBoolean],
    role: ['role', h.toString],
    userId: ['userId', h.toNumber],
    catalogId: ['catalogId', h.toNumber],
    catalogId2: ['catalogId', h.toNumber, h.toUndefined],
    catalogId3: ['catalogId', h.filterUndefined(function(input){
        // input always not undefined
        return input + '1';
    })],
    catalogId4: ['UndefinedCatalogId', h.filterUndefined(function(input){
        // input always not undefined
        return input + '1';
    })]
});


console.log('\n\n\n convert to boolean and to number \n\n', converter({
    "role": 2,
    "userId": '13',
    "catalogId": 'somethingLiteral'
}));

Result is:


{
    isGuest: true,
    role: '2',
    userId: 13,
    catalogId: NaN,
    catalogId3: 'somethingLiteral1'
}

Dict creates a dictionary and returns value by key.

to run unit test run

   npm test

v0.0.12

fixed package.json (thanks to alissonperez)

v0.0.11

sorry i've skipped several versions

Add toString helper and fix unit tests (by alissonperez)
clean package.json (by ahiipsa)

v0.0.9

fix for #10 "makeConverter modifies its arguments"
Add makeMapConverter (alexwhitman)

v0.0.8

make performance optimizations
add simple speed test "npm run speed"
some results https://docs.google.com/spreadsheets/d/1VO_DpwQq8RKOMKlN9RIXHjblha6n58qBpKWWGardIJo/edit?usp=sharing

v0.0.7

add unit tests
minor changes

v0.0.6

add example 'sentence test'
modify readme (make this more readable ;)
change jsdoc for functions

in feature

make normal unit tests and try to do some optimization for more performance
write more usage examples

Published

Vulnerabilities

Links

Maintainers

Keywords

Readme

json-mapper

How to use

Shut up and show me a SIMPLE convertion

Helpers

template and templateStrong

def

valOrDef

dict

toBoolean, toNumber, toString, toUndefined, filterUndefined

v0.0.11

v0.0.8

v0.0.7

v0.0.6

in feature