Benchmark: forEach & copy - MeasureThat.net

Script Preparation code:

            var wido = {};
            var wido2 = {};
            var wido3 = {};
            var wido4 = {};
            var wido5 = {};
            for (i = 0; i < 100; ++i) {
                wido['a' + i] = i;
            }

Tests:

reduce + Object.assign
Object.entries(wido).reduce( (res, [key, value]) => Object.assign(res, { [key]: value }), {}, );
reduce + assignmen
Object.entries(wido).reduce((res, [key, value]) => { wido2[key] = value; });
Object.keys.forEach + assignment
Object.keys(wido).forEach(key => { wido3[key] = wido[key]; });
Object.entries.forEach + assignment
Object.entries(([key, value]) => { wido4[key] = value; });
for + assignmen
for (key in wido) { wido5[key] = wido[key]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
reduce + Object.assign
reduce + assignmen
Object.keys.forEach + assignment
Object.entries.forEach + assignment
for + assignmen

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is a crucial task, and MeasureThat.net provides an excellent platform for benchmarking various scenarios.

**Benchmark Definition:**
The provided JSON represents a single benchmark definition with the following characteristics:

* The script preparation code creates five objects (`wido`, `wido2`, `wido3`, `wido4`, and `wido5`) and populates them with values using a `for` loop.
* The HTML preparation code is empty, indicating that no HTML-related work is performed in this benchmark.
* The individual test cases are represented by an array of objects, each containing a benchmark definition.

**Test Cases:**
The five test cases compare different approaches to assign values to the populated objects:

1. **reduce + Object.assign**: Uses `Object.entries()` to iterate over the object's key-value pairs and then reduces the array using `reduce()`, assigning each value back into a new object (`wido2`).
2. **reduce + assignment**: Similar to the previous test case, but directly assigns values to `wido2`.
3. **Object.keys.forEach + assignment**: Iterates over the keys of `wido` using `Object.keys()` and then uses `forEach()` to assign values to a new object (`wido3`).
4. **Object.entries.forEach + assignment**: Iterates over the key-value pairs of `wido` using `Object.entries()` and then uses `forEach()` to assign values to a new object (`wido4`).
5. **for + assignment**: Uses a traditional `for` loop to iterate over the keys of `wido` and assigns values to a new object (`wido5`).

**Library/Functions Used:**

* `Object.entries()`: Returns an array of key-value pairs for an object.
* `reduce()`: Reduces an array by applying a function to each element, returning a single value.

**Special JavaScript Features/Syntax:**
The benchmarks utilize the following features:

* **Arrow functions**: Used in tests 2 and 4 to define small anonymous functions.
* **Template literals**: Not explicitly used in any of the benchmarks.

**Pros and Cons:**

* **reduce + Object.assign**:
	+ Pros: Efficient use of `Object.entries()` and `reduce()`.
	+ Cons: May not be as readable or maintainable due to its concise nature.
* **reduce + assignment**:
	+ Pros: Similar to the previous test case, but with fewer lines of code.
	+ Cons: Same concerns regarding readability and maintainability.
* **Object.keys.forEach + assignment**:
	+ Pros: Easy to read and understand, as it explicitly uses `forEach()` on an array of keys.
	+ Cons: May not be as efficient due to the overhead of creating an array of keys.
* **Object.entries.forEach + assignment**:
	+ Pros: Similar to the previous test case, but with a more concise syntax.
	+ Cons: Same concerns regarding readability and maintainability.
* **for + assignment**:
	+ Pros: Easy to read and understand, as it uses a traditional `for` loop.
	+ Cons: May not be as efficient due to the overhead of iterating over keys.

**Other Alternatives:**

* Using `Object.keys()` instead of `Object.entries()`, which would require converting each key-value pair to an array of keys.
* Using a different method, such as `Map` or `Set`, to store and retrieve values.

Overall, these test cases help users understand the relative performance differences between various approaches to assigning values in JavaScript.

Related benchmarks:

forEach & copy (version: 0)

Comparing performance of: reduce + Object.assign vs reduce + assignmen vs Object.keys.forEach + assignment vs Object.entries.forEach + assignment vs for + assignmen

Created: 4 years ago by: Guest

Jump to the latest result

reduce + Object.assign

reduce + assignmen

Object.keys.forEach + assignment

Object.entries.forEach + assignment

for + assignmen

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):