Benchmark: Object vs Map 5 - MeasureThat.net

Script Preparation code:

const rnd = () => Math.random().toString(36);

  const base = Array.from({length: 200}, () => [rnd(), rnd()]);

  const rndKey = () => base[Math.floor(Math.random() * base.length)][0];

  const map = new Map(base);

  const obj = Object.setPrototypeOf(Object.fromEntries(base), null);

  const acc = []; 

  function testMap() {
    const newKey = rnd();

    map.set(newKey, rnd());

    acc.push(
      map.get(rnd()),
      map.get(rndKey())
    ); // doing actual work

    map.set(rndKey(), rnd());

    map.delete(newKey);

    eval('acc.push("' + rnd() + '");');   // disable optimisations
    acc.length = 0; 
  }

  function testObj() {

    const newKey = rnd();

    obj[newKey] = rnd();

    acc.push(
      obj[rnd()],
      obj[rndKey()]
    ) // doing actual work

    obj[rndKey()] = rnd();

    delete obj[newKey];

    eval('acc.push("' + rnd() + '");');  // disable optimisations
    acc.length = 0; // doing actual work
  }

Tests:

Map
testMap()
Obj
testObj()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map
Obj

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition**

The benchmark is designed to compare the performance of two data structures: `Object` and `Map`. The test creates an array of 200 objects, where each object has two properties (key-value pairs). The test then uses these arrays to create a `Map` and an `Object`, respectively. The `Map` is initialized using the `Array.from()` method and its key-value pairs are used as keys and values, respectively.

The test case consists of three main steps:

1. Initialize the map and object with random key-value pairs.
2. Perform some work on the data structures (e.g., adding new entries, deleting existing ones).
3. Measure the time taken to execute a function that pushes the results to an array (`acc`).

**Options Compared**

Two options are compared in this benchmark:

1. **Map**: The test creates a `Map` instance using the `Array.from()` method and its key-value pairs as keys and values, respectively.
2. **Object**: The test creates an `Object` instance using the `Object.fromEntries()` method and its key-value pairs as properties.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Map**:
	+ Pros: Maps are designed for key-value pairs and provide efficient lookups, insertions, and deletions. They are also more memory-efficient than objects.
	+ Cons: Maps have additional overhead due to the need to store keys and their associated values.
* **Object**:
	+ Pros: Objects are more flexible and can be used for a wider range of data structures, such as complex nested objects.
	+ Cons: Object lookups, insertions, and deletions can be slower than those in maps.

**Other Considerations**

In this benchmark, the test disables optimizations using `eval()` to ensure that the results are not influenced by the JavaScript engine's optimization techniques. Additionally, the test uses a large array of 200 objects to simulate a large dataset.

**Libraries and Special JS Features**

There is no specific library used in this benchmark. However, it does use some special JavaScript features:

* `Array.from()` method: Creates an array from an iterable object.
* `Object.fromEntries()` method: Creates an object from key-value pairs.
* `eval()` function: Evaluates a string as JavaScript code.

**Alternative Approaches**

Other alternatives to compare the performance of data structures include:

1. Using other data structures, such as arrays or sets.
2. Adding more complex operations (e.g., sorting, searching) to the test cases.
3. Using different algorithms for data storage and retrieval.
4. Measuring performance under different workload patterns.

It's worth noting that MeasureThat.net provides a wide range of benchmark templates and examples, allowing users to create and customize their own benchmarks for various JavaScript features and use cases.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:88.0) Gecko/20100101 Firefox/88.0

Browser/OS: Firefox 88 on Windows

View result in a separate tab

Test name	Executions per second
Map	62854.1 Ops/sec
Obj	50938.4 Ops/sec

Related benchmarks:

Object vs Map 5 (version: 0)

Comparing performance of: Map vs Obj

Created: 3 years ago by: Guest

Jump to the latest result

Map

Obj

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):