object-concat

Assigns properties of source object(s) to a new object.

npm install object-concat --save

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Example

basic

var concat = require('object-concat')

var defaults = { level: 1 }
var restored = { player: 'isaac', level: 5 }
var gamedata = concat(defaults, restored)

assert.equal(gamedata.player, 'isaac')
//=> undefined

assert.equal(gamedata.level, 5)
//=> undefined

assert.notDeepEqual(gamedata, defaults)
//=> undefined

assert.notDeepEqual(gamedata, restored)
//=> undefined

transform

var concat = require('object-concat')

var defaults = { level: 1 }
var restored = { player: 'isaac', level: 5 }
var gamedata = concat(defaults, restored, function (key, sourceVal, targetVal) {
  return key === 'player' ? sourceVal.toUpperCase() : sourceVal
})

assert.equal(gamedata.player, 'ISAAC')
//=> undefined

Features

• Concatenative inheritance.
• Return a new object instead of mutating a target object.
• Subsequent source properties overwrite previous.
• Supports optional iteratee function allowing transformation of target values.

Anti-Features

• Will never make you seed your parameter list with an empty object:
  • No _.extend({}, source)
• Will never mutate existing objects.
• Will never overwrite native Object prototype methods (i.e. Object.assign polyfills).

API

concat([sources], [iteratee])

Arguments

• [sources]: (…Object) The source objects.
• [iteratee]: (Function) Function that produces desired target value (must be last parameter).
  • key: (String) Object key name.
  • sourceVal: (*) Object source value.
  • targetVal: (*) Object target value.

Returns

• (Object) The new object.

Alternatives

Most, if not all of the alternatives listed have varying semantics so be careful which you choose for your own applications.

• lodash.assign
• underscore.extend
• object-assign
• object.assign

Licenses