Jango NPM | npm.io

Jango

Jango is a tiny alternative to Immutable.js. It weighs in at 1.14kb gzipped and has no dependencies.

Installation

npm install --save jango

Purpose

Jango was born out of a need for a much smaller Immutable.js. Its goal is to efficiently represent nested JavaScript data immutably, while providing one of the most compelling reasons to use immutable data: strict equality implies deep equality. In Jango, if any setter method doesn't result in any mutations, it returns itself, which means that === can be used for incredibly fast deep equality checks.

API

A "Jango" is an object created with the Jango factory that holds a single value. Its API consists of methods treating it as a recursive data structure, allowing it to represent and traverse JavaScript objects and arrays.

Jango()

Creates a Jango. Complex data structures passed to the factory are recursively converted.

var plain = Jango(1);

var object = Jango({one: 1, two: 2, three: 3});

var array = Jango([1, 2, 3]);

var nested = Jango({obj: {one: 1, two: 2, three: 3}, arr: [1, 2, 3]});

.val(key, options)

Recursively converts the value of the Jango object back to a JavaScript object. Pass a string or array to convert the value at that path.

options

shallow: only converts the root object, not any nested Jangos.

plain.val(); // 1

object.val(); // {one: 1, two: 2, three: 3}

array.val(); // [1, 2, 3]

nested.val(); // {obj: {one: 1, two: 2, three: 3}, arr: [1, 2, 3]}

nested.val(['obj', 'one']) // 1

obj.val({shallow: true}) // {one: Jango(1), two: Jango(2), three: Jango(3)}

.get(key)

Returns the Jango at the given key. Pass an array instead of a string to get a nested Jango.

object.get('one'); // Jango(1)

array.get(0); // Jango(1)

nested.get(['obj', 'three']) // Jango(3)

.set(key, value)

Replaces either the entire Jango or the given key with the given value. Pass an array key instead of a string to set a nested Jango.

Returns the same object if no mutation occurs.

plain.set(2); // Jango(2)

object.set('two', {three: 'four'}); // Jango({one: 2, two: {three: four}, three: 3})

array.set(0, 2); // Jango([2, 2, 3])

nested.set(['arr', 2], 4); // Jango({obj: {one: 1, two: 2, three: 3}, arr: [1, 2, 4]})

object.set('one', 1) === object; // true
object.set('three', 9) === object; // false

.merge(source)

Merges the source into the Jango, adding or replacing any keys in the source but leaving keys only in the destination.

Returns the same object if no mutation occurs.

object.merge({'one': 2}); // Jango({one: 2, two: 2, three: 3})

array.merge([2]); // Jango([2, 2, 3])

nested.merge({add: 'value'}); // Jango({add: 'value', obj: {one: 1, two: 2, three: 3}, arr: [1, 2, 4]})

.filter(fn)

Filters out keys or elements of the Jango for which the predicate returns false.

Returns the same object if no mutation occurs.

object.filter(function (item) { return item.val() !== 1; }); // Jango({two: 2, three: 3})

array.filter(function (item) { return item.val() !== 1; }); // Jango([2, 3])

array.filter(function (item) { return true; }) === object; // true
array.filter(function (item) { return item.val() + 1; }) === object; // false

.map(fn)

Maps keys or elements of the Jango to a new Jango.

Returns the same object if no mutation occurs.

object.map(function (item) { return item.val() * 2; }); // Jango({one: 2, two: 4, three: 6})

array.map(function (item) } return item.val() * 2; }); // Jango([1, 2, 3])

object.map(function (item) { return item; }) === object; // true
object.map(function (item) { return item.val() + 1; }) === object; // false

Comparisons

Immutable.js

The original inspiration for Jango. Immutable provides a large API, and collections that mirror ES6 iterable Maps and Sets. However, it's 18.8kb gzipped and likely provides much more functionality than your application needs.

Use Jango if:

Filesize is an important factor in your application

Use Immutable if:

You need a robust and set of methods for representing and manipulating your data

Freezer.js

A different approach to application development, Freezer also provides an event system so that you can build your application in a reactive way. However, it's less useful with libraries like Redux.

Use Jango if:

You need an immutable data structure to plug into your Redux store

Use Freezer if:

Your application is built reactively

Scour.js

Scour's main objective is to provide Lodash-like functionality to immutable objects. It has a large utility belt of methods and a small filesize, but operations that don't mutate the original object still return a new reference.

Use Jango if: