Benchmark: forEach vs reduce vs map vs filter vs for v2292U9I2JIR2J0IEJ02JE0IJ20EJzdDZD

Script Preparation code:

var arr = [];
for (var i = 0; i < 12345; i++) {
  arr[i] = i;
}

var obj = {};

Tests:

forEach
arr.forEach((item, index) => obj[index] = item);
reduce
sumReduce = arr.reduce((lastValue, item, index) => { return lastValue[index] = item; }, {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
reduce

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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**Benchmark Overview**

The provided benchmark measures the performance of various JavaScript array operations: `forEach`, `reduce`, and other approaches (`map` and `filter`) in comparison to a traditional `for` loop.

**Tested Options**

The benchmark compares the following options:

1. **forEach**: Iterates over an array using the `forEach` method, which executes the provided callback function once for each element.
2. **reduce**: Uses the `reduce` method to iterate over an array and accumulate a result.
3. **map** and **filter**: Similar to `forEach`, but with different purposes:
	* **map**: Creates a new array by executing the provided callback function on each element.
	* **filter**: Creates a new array containing only elements for which the provided callback function returns `true`.
4. **for** loop: A traditional, iterative approach using a `for` loop to iterate over an array.

**Pros and Cons of Each Approach**

1. **forEach**:
	* Pros: Easy to use, concise code.
	* Cons: May have performance overhead due to callback function execution.
2. **reduce**:
	* Pros: Efficient for accumulating results, can be used with initial values.
	* Cons: Can be less readable than other approaches, may not be suitable for all data types.
3. **map** and **filter**:
	* Pros: Can create new arrays, easy to use in some cases.
	* Cons: May have performance overhead due to array creation and callback function execution.
4. **for** loop:
	* Pros: Low-level control, efficient for simple iteration.
	* Cons: Requires explicit indexing, can be more verbose.

**Library Usage**

In the benchmark script preparation code, an object `obj` is created using `{}` syntax, which is shorthand for creating an empty object literal (`Object.create(null)` or `Object.assign({}, {})`). This is a standard JavaScript feature used to create an object with no prototype chain.

**Special JS Features/Syntax**

None mentioned in the provided benchmark definition.

**Other Alternatives**

For array iteration and manipulation, other approaches can be considered:

1. **Array.prototype.every()**, `Array.prototype.some()`: Similar to `filter` but return a boolean result instead of an array.
2. **Array.prototype.includes()**: Returns a boolean indicating whether an element is present in the array.
3. **Array.prototype.indexOf()`/`.lastIndexOf()`: Return the index of the first/last occurrence of an element in the array.
4. **Array.prototype.reduceRight()`: Similar to `reduce`, but executes from right to left.

Note that these alternatives may not be as widely supported or well-maintained, and some may have performance implications depending on the specific use case.

Related benchmarks:

forEach vs reduce vs map vs filter vs for v2292U9I2JIR2J0IEJ02JE0IJ20EJzdDZD (version: 0)

Comparing performance of: forEach vs reduce

Created: 5 years ago by: Guest

Jump to the latest result

forEach

reduce

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):