Benchmark: Map vs Obj Lookup

Script Preparation code:

var keys = [];
var map = new Map();
var obj = {};

for (let i = 0; i < 10000; i++) {
  const key = String.fromCharCode(i);
  keys.push(key);
  map.set(key, i);
  obj[key] = i;
}

Tests:

Map
keys.map(key => map.get(key))
Obj
keys.map(key => obj[key])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map
Obj

Fastest: N/A

Slowest: N/A

Latest run results:

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

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

**What is tested?**

The benchmark tests two different approaches to accessing an array of keys (`keys`) in a JavaScript object: using a `Map` data structure or directly indexing into an object (`obj`). The test measures which approach is faster.

**Options compared**

There are two options being compared:

1. **Using a Map**: This approach uses the `Map` data structure to store key-value pairs, where each key is from the `keys` array and its corresponding value is the same index from the array.
2. **Direct object indexing**: This approach directly accesses the `obj` object using bracket notation (`obj[key]`) to retrieve the value associated with each key in the `keys` array.

**Pros and cons of each approach**

1. **Using a Map**:
	* Pros: Maps provide fast lookups, with an average time complexity of O(1) for accessing elements by their keys.
	* Cons: Requires creating an instance of the `Map` class, which may have some overhead.
2. **Direct object indexing**:
	* Pros: Does not require creating any additional data structures or classes, making it a simple and straightforward approach.
	* Cons: Has a time complexity of O(n) for accessing elements by their keys, where n is the length of the `keys` array.

**Library used**

None in this specific case. However, note that the `Map` class is part of the JavaScript standard library.

**Special JS feature or syntax**

There are no special JavaScript features or syntaxes mentioned in this benchmark.

**Other alternatives**

Some alternative approaches could be:

* Using a `Set` data structure to store unique keys from the `keys` array.
* Implementing a custom lookup mechanism using a hash table or another data structure.
* Using a library like Lodash that provides optimized lookups and other utility functions.

It's worth noting that, in general, using a `Map` or `Object` with bracket notation is more idiomatic JavaScript than creating a custom implementation. The benchmark is likely intended to highlight the performance differences between these two approaches.

Related benchmarks:

Map vs Obj Lookup (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>

Fastest: N/A

Slowest: N/A

No previous run results

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