Benchmark: indexOf vs new Map

Script Preparation code:

var array = [];
for (var i=0; i<300; ++i) {
  	array.push('00' + i);
}

function hasWithIndexOf(needle) {
	return array.indexOf(needle) !== -1;
}

var map = new Map();
array.forEach(item => map.set(item, true));

function hasWithMap(needle) {
	return map.get(needle);
}

Tests:

indexOf
for (var i=0; i<100; ++i) { hasWithIndexOf('404'); }
map
for (var i=0; i<100; ++i) { hasWithMap('404'); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
indexOf
map

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 benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Purpose**

The primary goal of this benchmark is to compare the performance of two approaches: using `indexOf` (a built-in JavaScript array method) versus creating a new `Map` data structure to store an array of strings. The benchmark aims to measure which approach is faster for searching a specific value within the array.

**Options Compared**

Two options are being compared:

1. **Using `indexOf`:**
	* This method searches the array from left to right until it finds the specified element.
	* If the element is found, its index is returned; otherwise, `-1` is returned.
2. **Creating a new `Map`:**
	* A `Map` data structure is created and populated with an array of strings.
	* To search for a specific value, you use the `get()` method on the `Map`, passing the value to be searched as an argument.

**Pros and Cons**

Here's a brief overview of each approach:

### Using `indexOf`

Pros:

* Simple to implement
* Built-in method in JavaScript
* Efficient when the array is small or the search target is common

Cons:

* May have poor performance for large arrays or frequent searches
* Returns `-1` if not found, which can lead to unnecessary iterations if you assume the value will be present

### Creating a new `Map`

Pros:

* Fast lookup and insertion times (O(1) on average)
* Efficient for large datasets and frequent searches
* Avoids potential issues with `indexOf` returning `-1`

Cons:

* Requires more memory due to the additional data structure
* More complex implementation compared to using `indexOf`
* May require additional setup (e.g., creating the map, populating it)

**Library and Special JS Features**

This benchmark uses a JavaScript library: none. There are no special JavaScript features or syntax used beyond the standard ECMAScript 2015 (ES6) features.

**Other Considerations**

When choosing between these approaches, consider the following factors:

* Array size and frequency of searches
* Desired performance characteristics (e.g., fastest, most memory-efficient)
* Readability and maintainability of your code

In this specific benchmark, using a `Map` is expected to perform better due to its fast lookup times. However, for smaller arrays or less frequent searches, the simplicity and ease of use of `indexOf` might make it a more suitable choice.

**Alternatives**

Some alternative approaches you could consider:

* Using a `Set`: A `Set` data structure can provide faster membership testing than an array, but its performance may not be as good for searching a specific value.
* Implementing a custom search algorithm: Depending on your specific use case, you might need to implement a more efficient search algorithm that balances memory usage and performance.
* Using a different data structure altogether (e.g., a trie or a suffix tree): These data structures can provide fast lookup times but may be overkill for simple string searching tasks.

Keep in mind that the optimal approach depends on your specific requirements and constraints. This benchmark provides a starting point for comparison, but you should consider your own needs and preferences when choosing an implementation.

Related benchmarks:

indexOf vs new Map (version: 0)

Comparing performance of: indexOf vs map

Created: 3 years ago by: Guest

Jump to the latest result

indexOf

map

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):