Benchmark: Array loop vs foreach vs map, by objects

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 10000; i++) {
      arr[i] = {
        key : i,
        value : i *10
      };
    }

Tests:

for
for (var i = 0, len = arr.length; i < len; i++) { arr[i].value = arr[i].value * 3 * 8; }
map
arr = arr.map(item => { item.value = item.value * 3 * 8; return item; });
forEach
arr.forEach(function (item){ item.value = item.value * 3 * 8; })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
map
forEach

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 break down the benchmark and its various components.

**Benchmark Definition**

The benchmark defines three test cases:

1. `Array loop`: This test case uses a traditional `for` loop to iterate over an array and perform an operation on each element.
2. `foreach`: This test case uses the `forEach` method to iterate over an array and perform an operation on each element.
3. `map`: This test case uses the `map` function to create a new array with transformed elements.

**Options Compared**

The benchmark compares the performance of these three approaches:

* `Array loop`: A traditional `for` loop that iterates over the array using its length property.
* `foreach`: The `forEach` method, which is called on an array and executes a provided function for each element in the array.
* `map`: The `map` function, which creates a new array with transformed elements.

**Pros and Cons**

Here are some pros and cons of each approach:

* `Array loop`:
	+ Pros: Can be more efficient for small arrays or when specific control is needed over iteration.
	+ Cons: Can be slower for large arrays due to the overhead of checking the length property.
* `foreach`:
	+ Pros: More concise and readable than traditional loops, with less chance of off-by-one errors.
	+ Cons: May incur a slight performance penalty due to the function call overhead.
* `map`:
	+ Pros: Efficient for large arrays, as it avoids the need to check the length property and can return new values in place.
	+ Cons: Requires an additional array creation step, which can consume more memory.

**Library and Purpose**

The `forEach` method is a part of the ECMAScript standard and is used to execute a function for each element in an array. It's a convenient way to iterate over arrays without having to manually keep track of indices or lengths.

There is no additional library required for this benchmark.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax being tested in this benchmark. However, it's worth noting that the `map` function returns a new array with transformed elements, whereas `Array loop` and `foreach` modify the original array.

**Other Alternatives**

If you wanted to test other approaches, you might consider:

* Using a `while` loop instead of `for`
* Using `slice` or `splice` to create a new array
* Using a functional programming approach with `reduce`, `filter`, or `every`
* Testing the performance of different JavaScript engines (e.g., SpiderMonkey, V8)

Related benchmarks:

Array loop vs foreach vs map, by objects (version: 0)

compares Array loop vs foreach vs map, not with primitives

Comparing performance of: for vs map vs forEach

Created: 7 years ago by: Registered User

Jump to the latest result

for

map

forEach

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):