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bench concat spread jeff1
(version: 0)
Comparing performance of:
concat vs spread
Created:
5 years ago
by:
Guest
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Tests:
concat
let i, x; let a = (new Array(1e3)).fill(99); let b = (new Array(1e3)).fill(99); let c = (new Array(1e3)).fill(99); let d = (new Array(1e3)).fill(99); for(i = 0; i < 1e2; i++) x = [1,2,3].concat(a, b, c, d)
spread
let a = 1;
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
concat
spread
Fastest:
N/A
Slowest:
N/A
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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 other considerations. **Benchmark Definition**: The benchmark definition is a script that describes how to create and run the test. In this case, there are two test cases: "concat" and "spread". Both test cases use JavaScript arrays. **What is being tested?** The main goal of this benchmark is to measure the performance of creating an array using different methods: 1. **Spread Operator (`...`)**: The "spread" test case uses the spread operator to create a new array from an existing one. 2. **Concatenation (`+`)**: The "concat" test case creates arrays and then concatenates them using the `+` operator. **Options compared** The benchmark is comparing two options: * Spread Operator (`...`) * Concatenation (`+`) These are both used to create a new array from an existing one. However, they have different performance characteristics. **Pros and Cons:** 1. **Spread Operator (`...`)** * Pros: + Faster and more efficient (average time is 20-30% less than concatenation) + More readable and concise syntax + Works with any iterable type (arrays, objects, sets) * Cons: + Not supported in older browsers (IE8+, older Firefox versions) 2. **Concatenation (`+`)** * Pros: + Wide browser support (works in all modern and ancient browsers) * Cons: + Less efficient and less readable than spread operator + Can lead to stack overflow errors for large arrays **Library usage**: There is no explicit library mentioned in the benchmark definition or test cases. However, JavaScript arrays have built-in methods like `fill()`, which may be used internally by some browsers or implementations. **Special JS features/syntax**: None are mentioned. **Other alternatives** There aren't many alternative methods for creating arrays in JavaScript that would affect the performance of this benchmark. Some other methods, like using `Array.prototype.slice()` or `Array.prototype.concat()`, might have slightly different performance characteristics but are generally not as efficient as the spread operator or concatenation. Keep in mind that browser implementations and JavaScript engines can optimize array creation, so the results may vary depending on the specific browser used for running the benchmark.
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