split-object

split-object

Minimal tool for working with Objects using built-in functional Array methods.

split-object will split an Object into an Array of keys & values, allowing you to manipulate the Object using Array methods then join values back into an Object.

In comparison to for..in or Object.keys().forEach() an Array of the form [{key1: value1}, {key2: value2}] can be a far more natural & convenient structure to work with.

split-object has both a split and a join method, similar to how String#split/Array#join combine to convert back & forward between Strings & Arrays.

Post ES6 we might see some better methods for iterating over Objects.

Installation

npm install split-object

Usage

var salad = {
  apples: 1,
  bananas: 3,
  carrots: 2
}

var loudIngredients = split(salad).map(function(ingredient) {
  return {
    key:   ingredient.key.toUpperCase(),
    value: ingredient.value * 3
  }
})

// loudIngredients:
// [
//   { key: 'APPLES', value: 3 },
//   { key: 'BANANAS', value: 9 },
//   { key: 'CARROTS', value: 6 }
// ]

var loudSalad = split.join(loudIngredients)

// loudSalad:
// {
//    APPLES: 3,
//    BANANAS: 9,
//    CARROTS: 6
// }
//

Examples

Iterating Values

// with object-split
split(salad).forEach(function(kv) {
  console.log(item)
})

// without object-split
Object.keys(salad).forEach(function(key) {
  var item = salad[key]
  console.log(item)
})

// or
for (var key in salad) {
  var item = salad[key]
  console.log(item)
}

Chaining Transformations

// with object-split
var pieces = split(salad)
.map(function(kv) {
  kv.value = calculate(value)
  return kv
})
.map(function(kv) {
  kv.value = recalculate(value)
  return kv
})
var newSalad = split.join(pieces)

Without splitting the Object into a similar structure to split-object, you're stuck with losing the keys (which is acceptable if you can deduce keys from the value) or using multiple reduce calls/for..of iteration:

// without object-split
var newSalad = Object.keys(salad)
.reduce(function(obj, key) {
  var value = salad[key]
  obj[key] = calculate(value)
  return obj
}, {})
newSalad = Object.keys(newSalad)
.reduce(function(obj, key) {
  var value = newSalad[key]
  obj[key] = recalculate(value)
  return obj
}, {})

As you can see, split-object doesn't save a huge number of lines, but it saves on some complexity, enables chaining and removes the hassle of extracting the value from the object on each iteration.

License

MIT