Benchmark: forEach vs reduce vs map vs filter vs for Key Value finding

Script Preparation code:

var arr = [];
for (var i = 0; i < 12345; i++) {
  arr.push({i: i, n: i+2})
  
}

function someFn(i) {
  return (i * 3 * 8 / 1200 * 0.002 / 40 * 0.2);
}

var sumForEach = 0,
  sumReduce = 0,
  sumMap = 0,
  sumFilter = 0,
  sumFor = 0;

Tests:

forEach
arr.forEach(item => item['n'] > item['i']);
reduce
sumReduce = arr.reduce((lastValue, item) => { item['n'] > item['i']; });
map
arr.map(item => item['n'] > item['i']);
filter
arr.filter(item => item['n'] > item['i']);
for
for (var j = 0; j < arr.length; j++) { sumFor += arr[j]; arr[j]['n'] > arr[j]['i']; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
reduce
map
filter
for

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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**Overview of the Benchmark**

The provided JSON represents a JavaScript microbenchmark, specifically designed to measure the performance of various array manipulation methods: `forEach`, `reduce`, `map`, `filter`, and a custom `for` loop. The benchmark is run in Chrome 106 on a Windows desktop with a 64-bit architecture.

**Options Compared**

1. **forEach**: Iterates over the array, performing an action (in this case, checking if an element's 'n' property is greater than its 'i' property) for each iteration.
2. **reduce**: Reduces the array to a single value, applying a function (in this case, the same action as `forEach`) to each element and accumulating the results.
3. **map**: Creates a new array with the result of applying a function (in this case, the same action as `forEach`) to each element in the original array.
4. **filter**: Creates a new array containing only the elements that satisfy a condition (in this case, an element's 'n' property is greater than its 'i' property).
5. **for** (custom loop): A traditional, hand-written loop using a `for` statement to iterate over the array and perform the same action as the other methods.

**Pros and Cons of Each Approach**

1. **forEach**:
	* Pros: Easy to read, concise, and well-supported in modern JavaScript.
	* Cons: May have performance overhead due to its nature (it iterates over each element once).
2. **reduce**:
	* Pros: Can accumulate results efficiently by reusing the accumulator value.
	* Cons: May be slower than other methods due to the initial array reduction step and potential array mutability issues.
3. **map**:
	* Pros: Creates a new array with transformed elements, avoiding mutation of the original array.
	* Cons: Can have performance overhead due to creating a new array and iterating over each element.
4. **filter**:
	* Pros: Efficiently filters out elements that don't meet the condition, especially when combined with `map`.
	* Cons: May not be as readable as other methods due to its conditional nature.
5. **for** (custom loop):
	* Pros: Full control over iteration and optimization opportunities.
	* Cons: Can be error-prone and less readable than other methods.

**Library and Syntax Considerations**

The `someFn` function is used in each benchmark, but it's not related to the array manipulation methods being compared. It appears to be a utility function for calculating a specific value based on an input parameter (`i`). The library used here is vanilla JavaScript, with no external dependencies.

**Special JS Feature or Syntax**

There are no special features or syntaxes mentioned in this benchmark. All methods use standard JavaScript syntax and don't employ advanced features like async/await, Promises, or generators.

**Other Alternatives**

For comparison purposes, other alternatives to these array manipulation methods could include:

* `every` (equivalent to `forEach` but returns a boolean result)
* `some` (equivalent to `forEach` but returns a boolean result indicating at least one element meets the condition)
* `find` and `findIndex` (alternative ways to filter arrays using higher-order functions)

Keep in mind that these alternatives might not have the exact same performance characteristics as the methods being compared, depending on the specific use case and array size.

Related benchmarks:

forEach vs reduce vs map vs filter vs for Key Value finding (version: 0)

Comparing performance of: forEach vs reduce vs map vs filter vs for

Created: 3 years ago by: Guest

Jump to the latest result

forEach

reduce

map

filter

for

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):