Benchmark: Array vs Object vs Map vs WeakMap access (1)

Script Preparation code:

var map = new Map();
var weakMap = new WeakMap()
var array = [];
var object = {};

Tests:

Map.get
map.get("0");
WeakMap.get
weakMap.get("0")
array[0]
array[0]
object.a
object.a

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map.get
WeakMap.get
array[0]
object.a

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.84 Safari/537.36

Browser/OS: Chrome 99 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Map.get	17315616.0 Ops/sec
WeakMap.get	16098552.0 Ops/sec
array[0]	17428762.0 Ops/sec
object.a	17648476.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The benchmark measures the performance of accessing elements in different data structures: arrays, objects, maps, and weak maps. The comparison is done using the `get()` method for each data structure.

**Script Preparation Code**

The script preparation code creates four variables:

*   `map`: a new map object.
*   `weakMap`: a new weak map object.
*   `array`: an empty array.
*   `object`: an empty object.

These variables are created before running the benchmark, ensuring consistent starting conditions for each test case.

**Individual Test Cases**

Each test case measures the performance of accessing an element in one of the four data structures. The test cases are:

1.  **Map.get**: Accessing an element with `map.get("0")`.
2.  **WeakMap.get**: Accessing an element with `weakMap.get("0")`.
3.  **Array[0]**: Accessing the first element of the array (`array[0]`).
4.  **Object.a**: Accessing a property on the object (`object.a`).

**Library and Purpose**

*   None (none of these are using external libraries)

**Special JS Features or Syntax**

None mentioned.

Now, let's discuss the options compared in this benchmark:

*   **Map.get() vs WeakMap.get()**: Both methods access elements in their respective data structures. However:
    *   Map.get() is faster because it uses a direct lookup, while WeakMap.get() involves checking for existence and potentially resolving weak references.
    *   WeakMap.get() has the advantage of using less memory since it doesn't require storing keys in memory if they're not present.

*   **Array[0] vs Object.a**: These two access different types of data:
    *   Array[0] accesses an element at a specific index within an array.
    *   Object.a accesses a property on an object by name.
    *   Array[0] is likely faster because it involves direct memory access, whereas accessing properties in objects may require more overhead due to the need for looking up keys and handling potential null values.

**Pros and Cons of Different Approaches**

*   Using `Map.get()` has the following advantages:
    *   Faster lookup times
    *   Less memory usage
    *   Direct access to elements

However, it also has some disadvantages:
    *   May not work as expected for certain edge cases or with specific data structures.
*   Using `WeakMap.get()` has the following advantages:
    *   Less memory usage since weak references are used.
    *   More suitable for situations where keys might be missing.

However, it also has some disadvantages:
    *   Slower lookup times compared to direct access.
*   Accessing elements via array indices (`array[0]`) is generally faster because it involves direct memory access. However, this approach may not work well with all data structures or libraries.

**Other Alternatives**

Alternative approaches for accessing elements in arrays and objects include:

*   Using `Object.keys()` or `Array.prototype.indexOf()` to find the index of an element before accessing it at that index.
*   Using `in` operator to check if a property exists on an object before attempting to access it.

Keep in mind that these alternatives may introduce additional overhead, which could impact performance.

Related benchmarks:

Array vs Object vs Map vs WeakMap access (1) (version: 0)

Comparing performance of: Map.get vs WeakMap.get vs array[0] vs object.a

Created: 3 years ago by: Guest

Jump to the latest result

Map.get

WeakMap.get

array[0]

object.a

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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