Benchmark: indexOf vs map 002

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 = {};
array.forEach(item => map[item] = true);

function hasWithMap(needle) {
	return needle in map;
}

Tests:

indexOf
for (var i=0; i<100; ++i) { array.indexOf("404") !== -1; // array.indexOf("000") !== -1; }
map
for (var i=0; i<100; ++i) { const x = "404" in map }

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 dive into the benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark is designed to compare the performance of two approaches: using `indexOf` (a built-in JavaScript method) versus using an object literal (`map`) to check if a value exists in an array. The test cases are identical, but with different implementation details.

**Options Compared**

There are two options being compared:

1. **Using `indexOf`**: This approach uses the `indexOf` method to search for the specified value (`"404"` or `"000"`). If the value is found, it returns the index of the value; otherwise, it returns `-1`.
2. **Using an object literal (`map`)**: In this approach, an empty object is created and populated with all values from the array as keys. Then, a check is performed using the `in` operator to see if the specified value exists in the map.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Using `indexOf`**:
	+ Pros: Simple, straightforward, and well-established method.
	+ Cons: May be slower than other methods due to its linear search nature. Can return incorrect results if the array is modified concurrently.
* **Using an object literal (`map`)**:
	+ Pros: Often faster than `indexOf`, especially for large datasets, since it uses a hash table lookup. Eliminates the need for sequential searching.
	+ Cons: Requires more memory to store the object and its keys. Can be slower in some cases due to object creation overhead.

**Library/Functions Used**

In this benchmark, no external libraries or functions are used other than built-in JavaScript methods (`indexOf`, `map`, `forEach`).

**Special JS Features/Syntax**

There are a few special features being utilized here:

* The `in` operator is used to check if a value exists in the object. This is a common technique for checking membership in an object.
* The `const x = ... in map` syntax is using the `in` operator to assign a boolean result to a variable (`x`). This is a concise way to express a conditional statement.

**Alternatives**

If you're interested in exploring alternative approaches, here are some options:

* Using `filter()` or `some()` instead of `indexOf`
* Implementing your own custom lookup data structure (e.g., using a binary search tree)
* Utilizing modern JavaScript features like `Set` or `Map` objects for faster lookups
* Leveraging WebAssembly or native code for performance-critical applications

In summary, the benchmark is testing two approaches to checking if a value exists in an array: using `indexOf` versus using an object literal (`map`). The results can provide insight into which approach is generally faster and more efficient.

Related benchmarks:

indexOf vs map 002 (version: 0)

Comparing performance of: indexOf vs map

Created: 2 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):