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emptying an array
(version: 0)
Comparing performance of:
length zeroing vs assignment vs splice
Created:
6 years ago
by:
Registered User
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Tests:
length zeroing
var arr = [21,241,14,214,12,412,4,12,421,41,24,21]; arr.length = 0
assignment
var arr = [21,241,14,214,12,412,4,12,421,41,24,21]; arr = []
splice
var arr = [21,241,14,214,12,412,4,12,421,41,24,21]; arr.splice(0, arr.length)
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
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Test case name
Result
length zeroing
assignment
splice
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net. **Benchmark Definition JSON** The provided Benchmark Definition JSON represents a simple benchmark that tests how fast different approaches can empty an array. The "Script Preparation Code" is empty, which means no additional code needs to be executed before running the benchmark. Similarly, the "Html Preparation Code" is also empty. In essence, this benchmark is testing three different ways to reset the length of an array: 1. Directly setting `arr.length` to 0. 2. Assigning a new empty array `[]` to the variable `arr`. 3. Using the `splice()` method with arguments `(0, arr.length)`. **Options Compared** The three options compared in this benchmark are: * Direct assignment (`arr = []`) * Splice method (`arr.splice(0, arr.length)`) * Length zeroing (`arr.length = 0`) These approaches have different characteristics that might affect their performance: * **Direct Assignment**: Assigning a new empty array to `arr` is likely to be the fastest option since it creates a new object reference. However, this approach also involves a possible reassignment of variables in scope. * **Splice Method**: The `splice()` method modifies the original array and returns the removed elements. This approach might have a higher overhead due to the additional operation involved. On the other hand, it avoids creating a new array object. * **Length Zeroing**: Setting `arr.length` directly is likely to be faster than using an assignment or `splice()`, as it only updates the length property of the existing array. **Pros and Cons** Here are some pros and cons of each approach: * Direct Assignment: + Pros: Fastest, creates a new object reference. + Cons: May cause reassignment issues in scope, can lead to unexpected side effects. * Splice Method: + Pros: Avoids creating a new array object, potentially more predictable behavior. + Cons: May have higher overhead due to additional operation, modifies the original array. * Length Zeroing: + Pros: Fastest, avoids creating a new array object, and has minimal overhead. + Cons: Limited functionality (only sets length), might not be as intuitive as other approaches. **Library Used** None of the benchmark cases explicitly use any external libraries. However, it's worth noting that some libraries might provide optimized implementations for certain operations, such as array manipulation. **Special JS Feature or Syntax** There are no special JavaScript features or syntax used in these benchmark cases. They only rely on standard JavaScript syntax and built-in methods. **Other Alternatives** Some alternative approaches to empty an array could include: * Using `Array.prototype.fill(0)` or `Array.from([], () => 0)` * Creating a new array with `new Array(0)` and then using the `push()` method * Using a library like Lodash's `_.initial()` function Keep in mind that these alternatives might not be as fast as the benchmarked approaches, but they could provide more flexibility or convenience. I hope this explanation helps you understand the Benchmark Definition JSON and the individual test cases!
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