The primary maintainer of this project has not pushed the latest version to NPM, so we cloned and reference this repo directly from projects that need to utilize the updated version (specifically around a webpack bug).

dynamodb-update-expression

A small library providing the solution to generate DynamoDB update expression by comparing the original data with update/remove JSON object.

Release History

• 0.1.22 Issue #17, #19
• 0.1.21 Issue #10 Boolean values changing from true to false are not getting set
• 0.1.20 Issue #8 Remove colon characters from attribute names
• 0.1.19 fix the error when options is defined or null
• 0.1.18 remove extra logs from .17
• 0.1.17 Fix issue #7
• 0.1.16 Fix issue #6
• 0.1.15 updated the dependencies library, especially there is a fix for array object in deepmerge module
• 0.1.14 resolve #5 update the README.md
• 0.1.13 Cleaned up an unnecessary console.log for issue #3
• 0.1.0 Initial release

dynamodbUpdateExpression.getUpdateExpression(original, update, [options]);

See the options available below:

Installation

npm install dynamodb-update-expression --save

Usage

var dynamodbUpdateExpression = require('dynamodb-update-expression');

var updateExpression = dynamodbUpdateExpression.getUpdateExpression(original, update);
var removeExpression = dynamodbUpdateExpression.getRemoveExpression(original, remove);

Where original, update, and remove should be a JSON object.

For example:

Original JSON:

var original = {
  "firstName": "John",
  "lastName": "Doe",
  "phones": [
        "1111-2222-333",
        "5555-4444-555"
    ],
  "family": [
    {
      "id": 1,
      "role": "father"
    }
    ],
  "profile": {
    "jobTitle": "Manager",
    "company": "ACME Inc",
    "business": {
      "license": "ABCD-123-LIC",
      "website": "www.acme.com"
    }
  }
};

Update JSON:

var updates = {
  "lastName": "L. Doe", // Will be updated
  // List of primitives
  "phones": [
        "1111-2222-333", // Original will be MERGED with this list
        "2222-4444-555"
    ],
  // List of object
  "family": [
    {
      "id": 2,
      "role": "mother"
    } // Original will be REPLACED by this (because of: deepmerge library bug)
    ],
  // Nested Object
  "profile": {
    "office": "1234 Market Street", // Add this element
    "business": {
      "website": "www.acmeinc.com", // Update this element
      "phone": "111222333" // Add this element
    },
    "company": "" // Remove this element because it is an empty string
  }
};

Remove JSON:

var removes = {
  "phones": [
        "1111-2222-333" // Will remove this number
    ],
  "profile": {
    "business": {
      "website": "www.acmeinc.com", // Will remove this element
      "phone": "111222333" // Won't be removed (not exists in original)
    }
  }
};

Output

Sample output

The returned "updateExpression" object should be:

{
    "UpdateExpression": "SET #lastName = :lastName, #phones = :phones, #family = :family, #profilebusinesswebsite = :profilebusinesswebsite, #profilebusinessphone = :profilebusinessphone, #profileoffice = :profileoffice REMOVE #profilecompany",
    "ExpressionAttributeNames": {
        "#lastName": "lastName",
        "#phones": "phones",
        "#family": "family",
        "#profilebusinesswebsite": "profile.business.website",
        "#profilebusinessphone": "profile.business.phone",
        "#profileoffice": "profile.office",
        "#profilecompany": "profile.company"
    },
    "ExpressionAttributeValues": {
        ":lastName": "L. Doe",
        ":phones": [
            "1111-2222-333",
            "5555-4444-555",
            "2222-4444-555"
        ],
        ":family": [
            {
                "id": 2,
                "role": "mother"
            }
        ],
        ":profilebusinesswebsite": "www.acmeinc.com",
        ":profilebusinessphone": "111222333",
        ":profileoffice": "1234 Market Street"
    }
}

The returned "removeExpression" object should be:

{
    "UpdateExpression": "REMOVE #family, #profile.#business.#website SET #phones = :phones",
    "ExpressionAttributeNames": {
        "#profile": "profile",
        "#business": "business",
        "#website": "website",
        "#family": "family",
        "#phones": "phones"
    },
    "ExpressionAttributeValues": {
        ":phones": [
            "5555-4444-555",
            "9999-8888-777"
        ]
    }
}

Options

options.arrayMerge (only for update)

= default All values in any array will be merged.

= replaceMerge

Replace all values in any array of "original" object by the values inside "update" object

For example:

let original = {
  "firstName": "John",
  "lastName": "Doe",
  "phones": [
        "1111-2222-333",
        "5555-4444-555",
        "9999-8888-777"
    ],
  "family": [
    {
      "id": 1,
      "role": "father"
    }
    ],
  "profile": {
    "jobTitle": "Manager",
    "company": "ACME Inc",
    "business": {
      "license": "ABCD-123-LIC",
      "website": "www.acme.com"
    }
  }
};

let updates = {
  "lastName": "L. Doe", // Will be updated
  // List of primitives
  "phones": [
        "3333-6666-777", // Original will be MERGED with this list
        "2222-4444-555"
    ],
  // List of object
  "family": [
    {
      "id": 1,
      "role": "brother"
    },
    {
      "id": 2,
      "role": "mother"
    } // Original will be REPLACED by this (because of: deepmerge library bug)
    ],
  // Nested Object
  "profile": {
    "office": "1234 Market Street", // Add this element
    "business": {
      "website": "www.acmeinc.com", // Update this element
      "phone": "111222333" // Add this element
    },
    "company": "" // Remove this element because it is an empty string
  }
};

Result:

{ firstName: 'John',
  lastName: 'Doe',
  phones: [],
  family: [],
  profile:
   { jobTitle: 'Manager',
     company: 'ACME Inc',
     business: { license: 'ABCD-123-LIC', website: 'www.acme.com' } } }
Test Result {
    "UpdateExpression": "SET #lastName = :lastName, #phones = :phones, #family = :family, #profile.#business.#website = :profilebusinesswebsite, #profile.#business.#phone = :profilebusinessphone, #profile.#office = :profileoffice REMOVE #profile.#company",
    "ExpressionAttributeNames": {
        "#lastName": "lastName",
        "#phones": "phones",
        "#family": "family",
        "#profile": "profile",
        "#business": "business",
        "#website": "website",
        "#phone": "phone",
        "#office": "office",
        "#company": "company"
    },
    "ExpressionAttributeValues": {
        ":lastName": "L. Doe",
        ":phones": [
            "3333-6666-777",
            "2222-4444-555"
        ],
        ":family": [
            {
                "id": 1,
                "role": "brother"
            },
            {
                "id": 2,
                "role": "mother"
            }
        ],
        ":profilebusinesswebsite": "www.acmeinc.com",
        ":profilebusinessphone": "111222333",
        ":profileoffice": "1234 Market Street"
    }
}

Tests

mocha test.js

Contributing