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for vs foreach vs some vs for..of (short array)
(version: 0)
Compare loop performance
Comparing performance of:
for vs foreach vs some vs for..of
Created:
2 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var array = new Array(5);
Tests:
for
for (var i = 0; i < array.length; i++) { array[i]; }
foreach
array.forEach(function(i) { array[i]; });
some
array.some(function(i) { array[i]; });
for..of
for (var i of array) { array[i]; }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (4)
Previous results
Fork
Test case name
Result
for
foreach
some
for..of
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
2 years ago
)
User agent:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36
Browser/OS:
Chrome 120 on Mac OS X 10.15.7
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=490322" width="100%" height="500px"></iframe>
some
10.6M/s
foreach
10.5M/s
for..of
1.8M/s
for
1.2M/s
View exact numbers
Test name
Executions per second
✓
some
10,557,484 Ops/sec
foreach
10,541,890 Ops/sec
for..of
1,785,007 Ops/sec
for
1,167,943 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided JSON and explain what's being tested, compared, and the pros/cons of each approach. **Benchmark Definition** The benchmark compares the performance of four different loop constructs in JavaScript: 1. **For loop**: An old-school, manual incrementing loop that relies on `array.length` to iterate over the elements. 2. **forEach**: A built-in method that iterates over an array using a callback function. 3. **Some**: Another built-in method that returns a boolean value indicating whether at least one element in the array passes a test (in this case, just checking if any element exists). 4. **For...of loop** (ES6+): A new loop construct that uses a `for` expression to iterate over the elements of an array. **Script Preparation Code** The script starts by creating a new JavaScript array with 5 elements: ```javascript var array = new Array(5); ``` This will be the input for our benchmark. **Options being compared** Here's what each loop construct does, along with some pros and cons: 1. **For loop**: Manual incrementing loop that relies on `array.length`. Pros: simple, well-supported by older browsers. Cons: error-prone, slow, and less readable. 2. **ForEach**: Built-in method that iterates over an array using a callback function. Pros: concise, modern, and efficient. Cons: can be slower due to the overhead of a function call, and may not work in older browsers or Node.js versions before 4.x. 3. **Some**: Another built-in method that returns a boolean value indicating whether at least one element passes a test. Pros: simple, fast, and efficient. Cons: doesn't actually iterate over all elements (only stops when the condition is false), which might not be what you want for some use cases. 4. **For...of loop**: A new loop construct that uses a `for` expression to iterate over the elements of an array. Pros: concise, modern, and efficient. Cons: requires ES6+ support (older browsers may not understand this syntax). **Library usage** There is no explicit library mentioned in the provided code or benchmark definition. **Special JS feature or syntax** The For...of loop uses a special feature called **for...of loops**, which was introduced in ECMAScript 2015 (ES6). This allows you to iterate over an array using a more concise syntax than traditional for loops. This feature is widely supported by modern browsers and Node.js versions. **Other alternatives** For non-array elements, you can use other loop constructs like: * `while` loops * `do-while` loops * Recursive functions Keep in mind that the choice of loop construct ultimately depends on your specific use case, performance requirements, and target audience.
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