array-object-merge

Merge two objects with arrays of objects based on given object key(s)

Merge two objects with arrays of objects based on given object key(s) (identifier). Logic from object-array-merge is modified to support extra functionalities, then wrapped with lodash.mergeWith as customizer.

Supports multiple arrays with one or more identical object keys. Note that one object key can be used as an identifier for multiple arrays, but each array can only have one unique object key that will be used as its identifier. Objects not having the key will be ignored.

The intended use case for this package is to update documents in document-based database (e.g. MongoDB) following the definition of PATCH HTTP verb. This package tries to extend PATCH definition to array of objects (as in the request body can contains only changes, instead of an entire content (i.e. PUT HTTP verb)).

Limitations (as of 1.2.0)

• The result array currently is ordered alphanumerically according to the result of lodash.groupBy
• Does not support arrays with both object and primitive elements; only primitive elements of the update object remains. (See Examples section for code sample).
  Array of objects only or primitive only still work as expected.

Usage

Installation

# NPM
npm i array-object-merge

# Yarn
yarn add array-object-merge

CommonJS

const merge = require('array-object-merge')

merge(original, update, identifiers)

ES6

import merge from 'array-object-merge'

merge(original, update, identifiers)

Test

Clone this repository to your local environment, then:

cd /path/to/local/array-object-merge

# NPM
npm install
npm test
npm run coverage # Optional

# Yarn
yarn install
yarn test
yarn run coverage # Optional

Examples

/**
 * Merge two objects with one identifier
 */
let original = {
  arr: [{ id: 1, key: 'value' }, { id: 2, key: 'value' }]
}
let update = {
  arr: [{ id: 2, key: 'newValue' }, { id: 3, key: 'value' }],
  field: 'newkey'
}

/**
 * output = {
 *   arr: [
 *     { id: 1, key: 'value' },
 *     { id: 2, key: 'newValue' },
 *     { id: 3, key: 'value' }
 *   ],
 *   field: 'newkey'
 * }
 */
let output = merge(original, update, 'id')


/**
 * Merge two objects with multiple arrays and identifiers
 */
let original = {
  arr1: [{ id: 1, key: 'value' }, { id: 2, key: 'value' }],
  arr2: [{ _id: 1, key: 'value' }, { _id: 2, key: 'value' }]
}
let update = {
  arr1: [{ id: 2, key: 'newValue' }],
  arr2: [{ _id: 1, key: 'newValue' }],
  field: 'newkey'
}

/**
 * output = {
 *   arr1: [{ id: 1, key: 'value' }, { id: 2, key: 'newValue' }],
 *   arr2: [{ _id: 1, key: 'newValue' }, { _id: 2, key: 'value' }],
 *   field: 'newkey'
 * }
 */
let output = merge(original, update, [ 'id', '_id' ])


/**
 * Merge two objects with arrays of primitive values
 */
let original = {
  arr: [1, 2, 3, 4]
}
let update = {
  arr: [5, 6, 7, 8]
}

/**
 * Per REST specification: the update array will replace the original one
 * output = {
 *   arr: [5, 6, 7, 8]
 * }
 */
let output = merge(original, update)


/**
 * Merge two objects with one identifier and primitive values
 */
let original = {
  arr: [{ id: 1, key: 'value' }, { id: 2, key: 'value' }, 'shouldbegone']
}
let update = {
  arr: [{ id: 2, key: 'newValue' }, { id: 3, key: 'value' }, 'shouldbeincluded'],
  field: 'newkey'
}

/**
 * output = {
 *   arr: [
 *     { id: 1, key: 'value' },
 *     { id: 2, key: 'newValue' },
 *     { id: 3, key: 'value' },
 *     'shouldbeincluded'
 *   ],
 *   field: 'newkey'
 * }
 */
let output = merge(original, update, 'id')

Credits

• @tomgco, the author of object-array-merge, for basis of this pacakge.

License

This library is under an MIT License.