maskdata/documentation/replace_the_value_of_a_json_field.md

Node module to mask various kinds of data in the required formats

## Replace the value of a JSON field
To replace a value by keeping the type.
```javascript

const input = {
  name: "John",
  age: 33,
  married: true
}

let afterReplacing = MaskData.replaceValue(input, 'age', 99);
afterReplacing = MaskData.replaceValue(input, 'married', false);

//Output: 
Before replacing: {"name":"John","age":33,"married":true}
After replacing: {"name":"John","age":99,"married":false}

Type of age: number
Type of married: boolean

```

### Mask Multiple Fields
```javascript
const jsonInput = {
  cards: [
    {
      number: '1234-5678-8765-1234'
    },
    {
      number: '1111-2222-1111-2222'
    },
    {
      number: '0000-1111-2222-3333'
    },
    {
      name: "No card number here"
    }
  ],
  emails: {
    primaryEmail: 'primary@Email.com', 
    secondaryEmail: 'secondary@Email.com',
    moreEmails: ["email1@email.com", "email2@email.com", "email3@email.com", {childEmail: "child@child.com", secondChild: {nestedkid: "hello@hello.com"}}]
  },
  array: ["element1", "element22", "element333"],
  jwt: 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJsb2wiLCJuYW1lIjoiVGVzdCIsImlhdCI6ImxvbCJ9.XNDxZcBWWEKYkCiu6XFGmAeuPF7iFnI7Sdv91gVZJMU'
};

const jsonMaskConfig = {
  cardMaskOptions: { maskWith: "X", unmaskedStartDigits: 0, unmaskedEndDigits: 0},

  emailMaskOptions: { maskWith: "*", unmaskedStartCharactersBeforeAt: 0, 
  unmaskedEndCharactersAfterAt: 0, maskAtTheRate: false },

  stringMaskOptions: { maskWith: "?", maskOnlyFirstOccurance: false, values: [], maskAll: true, maskSpace: false },
  jwtMaskOptions: { maskWith: '*', maxMaskedCharacters: 32, maskDot: false, maskHeader: true, maskPayload: true, maskSignature: true},

  cardFields: ['cards[*].number'],
  emailFields: ['emails.*'],
  stringFields: ['array.*'],
  jwtFields: ['jwt']
}

const maskedOutput = maskData.maskJSON2(jsonInput, jsonMaskConfig);

// Output: 
{
  "cards": [
    {
      "number": "XXXX-XXXX-XXXX-XXXX"
    },
    {
      "number": "XXXX-XXXX-XXXX-XXXX"
    },
    {
      "number": "XXXX-XXXX-XXXX-XXXX"
    },
    {
      "name": "No card number here"
    }
  ],
  "emails": {
    "primaryEmail": "*******@*********",
    "secondaryEmail": "*********@*********",
    "moreEmails": [
      "******@*********",
      "******@*********",
      "******@*********",
      {
        "childEmail": "*****@*********",
        "secondChild": {
          "nestedkid": "*****@*********"
        }
      }
    ]
  },
  "array": ["????????", "?????????", "??????????"],
  "jwt": "************.**********.**********"
}

```

### Recursive Masking
If you want to mask all the fields with a name irrespective of its level in the json, use the `*{field_name}`. 

Example: 
```javascript

const inputJson = {
  car: "Mazda",
  addressLine1: "Mask me!",
  deeper: {
    addressLine1: "Mask me!",
    evenDeeper: { addressLine1: "Mask me!" },
  },
};

const fieldsToMask = ["*addressLine1"];  // Specify the field with a '*' at the beginning and NO dot(.) anywhere else in that field.

const jsonMaskConfig = {
  genericStrings: [
    {
      config: {
        maskWith: "*",
        maxMaskedCharacters: 6
      },
      fields: fieldsToMask
    },
  ],
};

const maskedOutput = maskData.maskJSON2(inputJson, jsonMaskConfig);

// Output: 
{
  car: 'Mazda',
  addressLine1: '******',
  deeper: { addressLine1: '******', evenDeeper: { addressLine1: '******' } }
}
```

Example 2: 
Using Recursive masking to mask card numbers in a json using mask card config. Recursive masking can be used to mask all types of data mentioned [here](#mask-json)

```javascript

const inputJson = {
  cards: [
    {
      number: "1234-5678-0123-0000"
    },
    {
      number: "1111-2222-3333-4444"
    },
    {
      number: "2222-4444-6666-8888"
    },
    {
      number: "1111-3333-5555-7777"
    },
    {
      number: "0000-0000-0000-0000"
    }
  ]
};

const cardfieldsToMask = ["*number"];  // Specify the field with a '*' at the beginning and NO dot(.) anywhere else in that field.
    
const jsonMaskConfig = {
  cardMaskOptions: {
        maskWith: "*",
        unmaskedStartDigits: 4,
        unmaskedEndDigits: 1
    },
  cardFields: cardfieldsToMask, 
};

const maskedOutput = maskData.maskJSON2(jsonInput, jsonMaskConfig);

// Output: 
{
  cards: [
    { number: '1234-****-****-***0' },
    { number: '1111-****-****-***4' },
    { number: '2222-****-****-***8' },
    { number: '1111-****-****-***7' },
    { number: '0000-****-****-***0' }
  ]
}
```


# Report Bugs 
If there is any help needed with the library functionalities or if there is any bug/issue, please raise an issue in GitHub: https://github.com/Sumukha1496/maskdata/issues

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# LICENSE - "MIT" 
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Copyright (c) 2019 Sumukha H S

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