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instanceof number
(version: 0)
Comparing performance of:
Instanceof vs blah
Created:
6 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
var test = [1,2,3,4]; var c;
Tests:
Instanceof
if (42 instanceof Number) { c++; }
blah
if (42 instanceof Number) { c++; }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
Instanceof
blah
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the world of JavaScript microbenchmarks. **What is tested?** The provided JSON represents two benchmark definitions: 1. A simple test case: `if (42 instanceof Number) { c++; }`. This test checks if the condition `42 instanceof Number` is true, where `Number` is a built-in JavaScript constructor that represents numbers. 2. Another identical test case with a different name: "Instanceof" and "blah". **Options compared** In this benchmark, two approaches are being tested: * **Direct check**: The `instanceof` operator is used directly to check if 42 is an instance of the `Number` constructor. * **Indirect check**: The test case uses a variable `c` that is initialized after the condition. If the condition is true, it increments `c`. This approach is essentially a benchmark for the indirect use of `instanceof`. **Pros and Cons** Direct check: Pros: * Simple and straightforward * No unnecessary computations or memory allocations Cons: * May involve more CPU cycles due to the operator itself Indirect check: Pros: * May be faster in some cases, as the increment operation might be optimized * Allows for more control over the execution flow Cons: * Introduces additional complexity and potential overhead due to variable initialization and incrementation **Other considerations** In JavaScript, `instanceof` is a binary operator that checks if an object is an instance of a particular constructor. It's not just about the type of the value, but also about the prototype chain. When using `instanceof`, JavaScript engine optimizes it by: * Skipping unnecessary checks for primitive values (e.g., numbers) * Using caching mechanisms to store the results of previous checks * Optimizing the lookup in the prototype chain **Library usage** In this benchmark, no external libraries are used. However, if a library like `lodash` or `core-js` were used, it would likely provide some utility functions for working with numbers and instanceof. **Special JS feature/syntax** There is no special JavaScript feature or syntax mentioned in the provided benchmarks. The tests only use standard JavaScript syntax. **Benchmark preparation code** The script preparation code is: ```javascript var test = [1,2,3,4]; var c; ``` This sets up an array `test` and initializes a variable `c`, which is not used anywhere else in the benchmark. **Other alternatives** If you wanted to measure this benchmark on different JavaScript engines or versions, MeasureThat.net provides options for: * Running benchmarks against multiple browsers (e.g., Chrome, Firefox) * Running benchmarks against different node.js versions * Running benchmarks against various engine types (e.g., V8, SpiderMonkey) Keep in mind that each of these alternatives may introduce additional overhead and variations in the benchmark results.
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