Benchmark: indexOf vs map (forked)

Script Preparation code:

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

Tests:

indexOf
for (var i=0; i<100; ++i) { hasWithIndexOf('404'); }
obj
for (var i=0; i<100; ++i) { hasWithObj('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
obj
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):

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**Benchmark Purpose:**
The benchmark measures the performance of three approaches to check if an element exists in an array or object: `indexOf`, `obj` (using the `in` operator), and `map`. The purpose is to compare the efficiency of these methods for different types of data structures.

**Options Compared:**

1. **`indexOf"`**: This method uses the `Array.prototype.indexOf()` function to search for an element in the array. It returns the index of the first occurrence of the specified value, or -1 if it's not found.
2. **`obj` (using `in` operator)**: This method uses the `in` operator to check if a key exists in the object. If the key is present, the expression evaluates to true; otherwise, it returns false.
3. **`map`**: This method uses the `Map.prototype.has()` function to search for an element in the map. It returns a boolean indicating whether the specified value is present in the map.

**Pros and Cons:**

1. **`indexOf`**:
	* Pros: Efficient for arrays with unique elements, as it can stop searching once it finds the first match.
	* Cons: May perform poorly for arrays with duplicate elements or large datasets.
2. **`obj` (using `in` operator)**:
	* Pros: Fast and efficient, even for large objects, since it uses a simple key lookup.
	* Cons: May not be suitable for all data structures, like arrays or maps, where the `in` operator may not work as expected.
3. **`map`**:
	* Pros: Similar performance to the `obj` method, and is designed specifically for key-value pairs, making it suitable for maps.
	* Cons: May be slower than other methods for large datasets or arrays with unique elements.

**Libraries Used:**

1. None explicitly mentioned in the benchmark definition code.
2. However, `Map.prototype.has()` uses the built-in `Map` object and its implementation is specified by ECMAScript standards.

**Special JavaScript Features/Syntax:**

* The use of the `for...of` loop (not explicitly used here) is a modern JavaScript feature that allows for iterating over iterable objects, like arrays or maps.
* The `const` keyword is used to declare constants, which helps prevent variable reassignment and improves code readability.

**Other Alternatives:**
For checking if an element exists in an array:

* Using `includes()` (ECMAScript 2019 and later): This method is similar to `indexOf`, but it's more efficient and doesn't require the specified value to be present at the beginning of the array.
* Using a custom implementation with binary search: This approach can provide good performance for large datasets, but it requires more code and may not be as readable.

For checking if an element exists in an object:

* Using `in` operator (as shown in the benchmark)
* Using `Object.prototype.hasOwnProperty()`: This method is similar to the `in` operator, but it's more explicit and might be preferred by some developers.
* Using a custom implementation with a hash table: This approach can provide good performance for large datasets, but it requires more code and may not be as readable.

Related benchmarks:

indexOf vs map (forked) (version: 0)

Comparing performance of: indexOf vs obj vs map

Created: 3 years ago by: Guest

Jump to the latest result

indexOf

obj

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):