AssignNoConflict

Safely merges Objects without overriding keys

Installing

npm install assign-no-conflict

Why?

There are times... yes there can be times... where you only want to merge objects if they do not have keys that override each other.

Prerequisites

ES5 Support (node 6.4.0 or higher)

Usage

Merging 3 objects that have no conflicts together:

const assign = require('assign-no-conflict')

const abc = assign({
  a: 1
}, {
  b: 2
}, {
  c: 3
})

const conflictState = typeof abc === 'string'
  ? `key "${abc}" already exists`
  : 'no conflicts'

console.log(conflictState)
// no conflicts
console.log(abc)
/*
{
  a: 1,
  b: 2,
  c: 3,
}
*/

Merging 3 objects that have conflicts:

const assign = require('assign-no-conflict')

const abc = assign({
  a: 1
}, {
  b: 2
}, {
  a: 3 // repeated key
})

const conflictState = typeof abc === 'string'
  ? `key "${abc}" already exists`
  : 'no conflicts'

console.log(conflictState)
// key "a" already exists
console.log(abc)
// a

What about Object.assign?

This module mainly has two differences with Object.assign:

• If no conflicts, it will return a new Object, no need to pass an empty object at the beginning.
• If there are conflicts it will return the key that introduces the conflict. You can check the return type, if its a string, then you can tell there are conflicts and which is the key that caused it.

NOTE: This module does not deep merge Objects.

Heads up

Only use this module if you specifically need to check for conflicting keys, otherwise you might be better off using good old Object.assign.

Running the tests

To run tests

npm run install
npm run test

Versioning

Im using SemVer for versioning. For the versions available, see the tags on this repository.

License

This project is licensed under the MIT License - see the LICENSE.md file for details.