Benchmark: Map vs Array vs Object set uint32 key speed

Script Preparation code:

var map = new Map();
var arr = [];
var obj = {};

var randomU32 = function() {
	return Math.random() * (1 << 31) >>> 0;
}

Tests:

Map
map.set(randomU32(), true);
Array
arr[randomU32()] = true;
Object
obj[randomU32()] = true;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map
Array
Object

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON benchmark definition and its test cases to understand what is being tested, compared, and their pros and cons.

**Benchmark Definition:**

The benchmark defines three data structures:

1.  **Map**: A `Map` object in JavaScript is a collection of key-value pairs where each key is unique and maps to a specific value.
2.  **Array**: An array is an ordered collection of values that can be accessed by index (position) using square brackets (`[]`).
3.  **Object set**: An object set in JavaScript is essentially a `Map`, but with the syntax of objects.

The script preparation code creates instances of these data structures: `map`, `arr`, and `obj`. The `randomU32` function generates a random unsigned 32-bit integer value used as keys for the map and array.

**Options Compared:**

These test cases compare the performance (speed) of:

1.  **Map**: Using a `Map` object to store values with unique integers as keys.
2.  **Array**: Using an array to store values, where each index corresponds to a unique integer key generated by the `randomU32` function.

**Pros and Cons:**

*   **Map**:
    *   Pros:
        *   Fast lookups due to hash-based indexing.
        *   Efficient insertion and deletion of elements.
    *   Cons:
        *   May have higher overhead for large datasets, as it requires more memory and complex internal data structures.
*   **Array**:
    *   Pros:
        *   Generally has lower memory overhead compared to `Map`.
        *   Simpler internal data structure, which can result in faster iteration and indexing operations.
    *   Cons:
        *   Slower lookups due to sequential indexing (index \[key\]) which requires calculating the index before accessing the value.

**Other Considerations:**

*   **Object Set**: The "Object set" option is essentially equivalent to using a `Map`, as both provide fast lookups and efficient insertion/deletion of elements. However, the syntax for object sets might be less familiar or intuitive to some developers.
*   **Device/Platform Variability**: The benchmark results shown are from Firefox 102 on Windows 7 Desktop devices. This means that there may be variations in performance across different browsers, versions, operating systems, and device types.

**Alternative Approaches:**

1.  **Sparse Sets**: Some data structures like sparse sets or sparse maps can provide a trade-off between storage efficiency and lookup speed.
2.  **Linked Hash Tables**: Other implementations, such as linked hash tables, might offer better performance in certain scenarios by avoiding the overhead of multiple pointers for each node.

In general, when dealing with large datasets or applications requiring fast lookups, `Map` objects are often a good choice due to their efficient indexing mechanism and scalability. However, specific use cases may require more tailored approaches based on factors like memory constraints, iteration requirements, and desired performance characteristics.

Related benchmarks:

Map vs Array vs Object set uint32 key speed (version: 0)

Comparing performance of: Map vs Array vs Object

Created: 9 years ago by: Guest

Jump to the latest result

Map

Array

Object

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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