Analyzing Key Changes in Redux v5.0.1: Object.create(null) Support

Anton Ioffe - January 3rd 2024 - 9 minutes read

In the ever-evolving world of JavaScript development, reimagining the way we handle state management often catalyzes profound innovation. With the release of Redux v5.0.1 comes a nuanced yet impactful leap into mutable state territory—courtesy of Object.create(null) support. This strategic update is more than a mere tweak; it's a paradigmatic shift, offering a new tier of state purity and performance optimization. Join us in dissecting this significant redux enhancement as we explore its benefits, weigh the performance implications, navigate the nuanced edge cases, and carve out new best practices for an era where 'clean slate' objects redefine the architecture of our applications' heart—the state. Embrace the learning curve and prepare for an insightful dive into Redux's transformation and how it's set to shape the framework of modern web development.

Understanding Object.create(null) in JavaScript

When you create an object in JavaScript using an object literal (e.g., {}), the newly created object inherits properties and methods from Object.prototype. This could have unintended side effects, especially when using the object as a map to store arbitrary keys assigned to values. Keys such as toString or hasOwnProperty that are part of Object.prototype can collide with the intended usage of the object as a pure key-value map.

Object.create(null) addresses this issue by creating an object that does not inherit from Object.prototype, commonly referred to as a "dictionary object". This means it has no built-in properties or methods, such as toString, hasOwnProperty, or any other method normally found on a plain JavaScript object. A dictionary object is a wholly clean slate, making it ideal for situations where objects are used purely to store data without concern for property collisions.

The lack of prototype inheritance in objects created with Object.create(null) eliminates the need to guard against edge cases that arise from enumerable properties on Object.prototype. For instance, iterating over an object with a loop or using methods like Object.keys() on a dictionary object will only yield properties that have been explicitly set on that object. This minimizes the risk of unexpected behavior due to inherited properties.

Moreover, the use of Object.create(null) can help prevent prototype pollution attack vectors, where adversaries could manipulate the behavior of an application by modifying the Object.prototype. Since dictionary objects don't inherit from Object.prototype, they are immune to changes in the prototype chain, making them a safer choice for certain applications that manipulate and store user-provided keys.

All in all, Object.create(null) creates objects that are tailored for low-level data storage by ensuring that there are no inherited defaults. This results in cleaner, more predictable objects free from the nuances that come with JavaScript's built-in object prototype chain. Being aware of and utilizing this distinction allows developers to more effectively manage data structures in a way that aligns with their unique requirements for storing and manipulating key-value pairs.

Redux v5.0.1 and Object.create(null): The Transition

In Redux v5.0.1, a crucial transformation has been set into motion with the use of Object.create(null) to establish the default state within reducers. This seemingly small yet radical change adheres to Redux's cardinal rules—ensuring that state management remains as pure and immune to mutations as possible. This update impacts how state objects behave, especially regarding their interaction with JavaScript's inherent object behaviors.

Traditionally, if the state was created with object literals or simple object constructors, it could inadvertently be exposed to changes in Object.prototype. By shifting to Object.create(null), Redux eliminates any unintended interaction with the prototype chain. As a result, the state becomes a purer map, devoid of irrelevant properties or behaviors. It's akin to starting with a blank slate, where the data structure is expected only to contain what is explicitly defined, making it an ideal choice for a well-contained state management environment.

This change serves to bolster immutability in Redux, a principle that lies at the heart of predictable state management. Since Object.create(null) constructs an object without a prototype, there is no longer the risk of prototype methods altering the state inadvertently through a shared prototype. State objects are now more robust against mutations, which might occur due to the methods inherited from Object.prototype, such as hasOwnProperty, or accidental additions to the prototype chain from third-party libraries or other code in the application.

The adoption of Object.create(null) also amplifies reducer purity. Reducers are expected to manage transitions from one state to another without causing side effects. Starting with an object that doesn’t inherit from Object.prototype dispenses with the need to defensively guard against the prototype's default properties or any changes it might suffer. Reducers can operate on the assumption that they are manipulating a state object with known properties, which aligns perfectly with the paradigm of pure functions.

This update does more than refine the technical underpinnings of Redux; it prescribes a more reliable state management blueprint. Developers are afforded a heightened assurance that the state object upholds Redux's intentions, untainted by external modifications. Such a structure lends itself to easier debugging, testing, and comprehension, allowing developers to focus their energies on the application features rather than on state-related quirks.

Performance Considerations and Benchmarking

In the realm of Redux-managed applications, the advent of Redux v5.0.1's support for Object.create(null) warrants a close examination of performance metrics. When comparing traditional JavaScript objects with Object.create(null) state objects, one of the key factors is memory footprint. Conventional objects carry the weight of the prototype chain, which, although negligible in small-scale applications, can add up in larger state trees. The introduction of Object.create(null) objects, stripped of the prototype overhead, could potentially result in a reduced memory footprint. However, the actual impact is highly dependent on the number and complexity of objects within the state.

Concerning access time, Object.create(null) objects are free from the lookup time associated with prototype chains. This characteristic promises faster property access, especially when dealing with a flat structure where most properties are accessed directly. To illustrate the difference, consider the following benchmark code snippet:

const traditionalObject = {};
const nullObject = Object.create(null);

console.time('Traditional Object Access');
for (let i = 0; i < 100000; i++) {
    traditionalObject['prop' + i] = i;
    let temp = traditionalObject['prop' + i];
console.timeEnd('Traditional Object Access');

console.time('Null Object Access');
for (let i = 0; i < 100000; i++) {
    nullObject['prop' + i] = i;
    let temp = nullObject['prop' + i];
console.timeEnd('Null Object Access');

In this expanded benchmark, the console.time() method measures the duration of property assignments along with retrieval operations, shedding light on both write and read access times during typical state interactions.

Another aspect to consider is the implication on garbage collection. Since Object.create(null) objects do not carry the prototype chain, they could be collected more efficiently when they fall out of scope. This reduced "garbage collection pressure" can lead to a more responsive application, particularly in scenarios with frequent state updates and disposals.

Yet it is critical to recognize that these performance benefits must be balanced with potential increases in code complexity. Developers accustomed to traditional object paradigms may need to adjust their approach. One common mistake is trying to use non-existent methods, such as .hasOwnProperty on Object.create(null) objects. Here is the correct approach:

function hasProperty(obj, prop) {
    return, prop);

This function leverages the hasOwnProperty method from the Object class to safely check for properties on dictionary-like objects created via Object.create(null).

For developers to make informed decisions about incorporating Object.create(null) into their Redux-managed applications, hands-on profiling is imperative. Tools like the Redux DevTools Extension can be leveraged for performance monitoring, capturing the change rate and duration of state updates. Additionally, JavaScript profilers built into browsers offer a way to zoom into heap snapshots and inspect garbage collection frequency and duration. Through targeted benchmarking and profiling, benefits such as reduced memory utilization and enhanced garbage collection can be weighed against any potential trade-offs in complexity or learning curve.

Edge Cases and Potential Pitfalls

One common mistake encountered when working with Redux v5.0.1 and [Object.create(null)]( state objects is the improper usage of object prototype methods such as hasOwnProperty, which would result in a TypeError because the state object does not inherit from Object.prototype. Here's an example of incorrect usage:

// Incorrect usage of hasOwnProperty
function myReducer(state, action) {
    // This will throw TypeError: state.hasOwnProperty is not a function
    if (state.hasOwnProperty(action.key)) { 
        return { ...state, [action.key]: action.value };
    return state;

To avoid this, developers should use to safely check for properties or use the in operator for existence checks:

// Correct usage of hasOwnProperty on an object without prototype
function myReducer(state, action) {
    if (, action.key)) {
        return { ...state, [action.key]: action.value };
    return state;

Serialization issues may also arise due to JSON methods assuming the existence of the default object prototype. Serializing an Object.create(null) state can lead to the loss of intended object behavior or structure, since JSON serialization and deserialization rely on standard objects with prototypes. Here's the incorrect approach to serializing such objects:

// Incorrect serialization of state object
function serializeState(state) {
    return JSON.stringify(state); // May not work as expected

The solution is either to avoid direct serialization of Object.create(null) objects or to convert them back to regular objects before serialization:

// Correct serialization of state object without a prototype
function serializeState(state) {
    const stateWithPrototype = { ...state };
    return JSON.stringify(stateWithPrototype);

Another potential pitfall is the misuse of standard object utilities and functions which do not apply to Object.create(null) objects, such as Object.keys or _.extend from libraries like Lodash. These utilities may work differently or not at all with objects lacking a prototype. Correct usage involves utilities that treat the input object as a mere collection of properties:

// Correctly merging a plain object into state without a prototype
import { assignIn } from 'lodash'; // Lodash function that does not rely on prototypes

function mergeIntoState(state, updates) {
    return assignIn({}, state, updates);

Lastly, consider the alterations to iteration behavior. Iterating over a standard object and an object created via Object.create(null) may result in different outputs if the iteration assumes prototype-presence.

// Correct iteration over state object without a prototype
function listStateProperties(state) {
    return Object.keys(state).forEach(key => {
        console.log('Property:', key, 'Value:', state[key]);

Always be mindful of the assumptions your code makes about object inheritance and prototype behavior to ensure compatibility with Redux v5.0.1's support of objects with null prototypes.

New Patterns and Best Practices with Object.create(null) in Redux

When utilizing Object.create(null) to structure Redux state, we enter a new era of state management best practices. This approach calls for a review of our architectural paradigms—do we consider the state object merely a container, or an instance with potential methods and behaviors? Adopting Object.create(null) signifies a shift towards viewing state as a pure data structure—a disciplined ledger of our application's history and a vanguard against unpredictable mutations.

In a Redux landscape shaped by Object.create(null), developers are encouraged to re-evaluate modularity and reusability, especially when decomposing the application's state. By designing our reducers to return these "clean-slate" objects, we enhance encapsulation and predictability in our code. However, this demands a transition strategy for existing codebases. Migrating to this new pattern might involve wrapping legacy state fragments with the appropriate boilerplate, ensuring seamless merges into the Object.create(null) paradigm. Transitioning is non-trivial and may require incremental adoption, but the payoff is the clarity and robustness in state interactions.

The role of plain objects in state management is a charged topic. Developers should consider if their current state structures are artifacts of convenience or thoughtfully chosen data stores. Object.create(null) adoption presses us to question if these structures truly align with state management philosophies wherein immutability and purity are paramount. Could this enshrine a new "golden path" in JavaScript state management, foregoing the vestiges of prototype chains for something more utilitarian?

Thought-provoking questions around this paradigm also touch on the broader JavaScript ecosystem. As libraries and frameworks evolve in response to language enhancements, so too must our approaches to state management. Could leveraging Object.create(null) potentially lead to state-specific utility libraries or methods that compensate for the lack of prototype-based utilities? Will this decision invariably cascade into the design choices made throughout the lifecycle of our applications, from the reducers to the selectors, effects, and sagas?

With new patterns come new responsibilities—developers must ensure they are not merely following trends but are making architectural choices that benefit their applications' maintainability and scalability. As we embrace Object.create(null) within Redux, careful consideration and discussion among teams are crucial. How does this change impact our existing codebase, and what are the potential benefits and challenges in adopting such a practice? Are we prepared for the ripple effects it may have on debugging, serialization, and state handling? Our choices today will undeniably shape the robustness and resilience of applications in an increasingly complex web ecosystem.


The article "Analyzing Key Changes in Redux v5.0.1: Object.create(null) Support" explores the significant update to Redux that introduces Object.create(null) support. This update enhances state purity and performance optimization by eliminating unintended side effects and the risk of prototype pollution. The article discusses the benefits, performance considerations, edge cases, and best practices of using Object.create(null) in Redux. It challenges developers to evaluate their current state management practices and consider the implications and potential trade-offs of adopting Object.create(null) in their applications. A challenging task for readers is to refactor their existing Redux code to incorporate Object.create(null) and assess the impact on state handling and debugging.

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