Benchmark: Map vs object for deletions

Script Preparation code:

var testMap = new Map();
var testObj = {};

Tests:

Add to Map
testMap.set('testKey', 1);
Add to object
testObj.testKey = 1;
Delete from Map
testMap.delete('testKey');
Delete from object
delete testObj.testKey;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Add to Map
Add to object
Delete from Map
Delete from object

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0) Gecko/20100101 Firefox/138.0

Browser/OS: Firefox 138 on Windows

View result in a separate tab

Test name	Executions per second
Add to Map	18787948.0 Ops/sec
Add to object	538319104.0 Ops/sec
Delete from Map	35772844.0 Ops/sec
Delete from object	31625660.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested.

**Benchmark Definition**

The benchmark is designed to compare the performance of two data structures in JavaScript: Maps (introduced in ECMAScript 2015) and objects.

**Options Compared**

Two options are being compared:

1. **Maps**: A Map is a data structure that stores key-value pairs, where each key is unique and maps to a specific value.
2. **Objects**: An object is an unordered collection of key-value pairs, where each key is a string or symbol and maps to a specific value.

**Pros and Cons**

**Maps:**

Pros:

* Fast lookup, insertion, and deletion operations (O(1) average case)
* Efficient use of memory for large datasets

Cons:

* May have slower creation times compared to objects
* Not as widely supported in older browsers or JavaScript engines

**Objects:**

Pros:

* Faster creation times compared to Maps
* Wide support across older browsers and JavaScript engines

Cons:

* Slower lookup, insertion, and deletion operations (O(n) average case)
* May lead to memory leaks if not properly managed

**Library and Purpose**

None mentioned in the provided benchmark. However, it's worth noting that some libraries like Lodash or Ramda provide optimized implementations of Maps and objects for performance-critical code.

**Special JS Feature or Syntax**

None mentioned in the provided benchmark.

**Other Considerations**

When choosing between using a Map or an object for data storage, consider the following factors:

* Performance: If you need fast lookup, insertion, and deletion operations, use a Map.
* Memory usage: If memory efficiency is crucial, use a Map.
* Browser support: If you need to support older browsers or JavaScript engines, use an object.

**Alternatives**

Other alternatives for data storage in JavaScript include:

1. **Sets**: Introduced in ECMAScript 2015, Sets provide fast membership testing and insertion/deletion operations (O(1) average case).
2. **WeakMaps**: Introduced in ECMAScript 2015, WeakMaps provide a way to store objects as values in a Map, allowing for efficient garbage collection.
3. **Arrays**: Arrays are a more traditional data structure that can be used for storing key-value pairs or other types of data.

Keep in mind that the choice of data structure ultimately depends on the specific requirements and constraints of your project.

Related benchmarks:

Map vs object for deletions (version: 0)

Checks the performance of deletions and additions to Maps vs objects

Comparing performance of: Add to Map vs Add to object vs Delete from Map vs Delete from object

Created: 4 years ago by: Registered User

Jump to the latest result

Add to Map

Add to object

Delete from Map

Delete from object

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):