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Array vs. object (great)
(version: 0)
Comparing performance of:
Object lookup vs Array lookup
Created:
3 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
var obj = { 1: true, 2: false, 3: true, 4: false }; var arr = [...new Array(100000), 1];
Tests:
Object lookup
obj[1] !== undefined
Array lookup
arr.find(x => x === 1)
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
Object lookup
Array lookup
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 break down the provided JSON data and explain what's being tested. **Benchmark Definition** The benchmark is designed to compare the performance of two approaches: using an object (with dot notation) versus using an array (with indexing). **Script Preparation Code** The script preparation code creates two variables: * `obj`: a JavaScript object with four properties (1, 2, 3, and 4), where each property has a boolean value. The purpose of this object is to provide a test case for looking up a specific property (in this case, `obj[1]`). * `arr`: an array created by first creating a new array with 100,000 elements using the spread operator (`...new Array(100000)`), and then appending a single element (`1`). The purpose of this array is to provide a test case for finding a specific element. **Html Preparation Code** The HTML preparation code is empty, which suggests that the benchmarking tool doesn't require any specific HTML setup or rendering to run the tests. **Individual Test Cases** There are two individual test cases: * **Object lookup**: Tests whether the expression `obj[1]` returns a boolean value (true). * **Array lookup**: Tests whether the expression `arr.find(x => x === 1)` returns an array with a single element (`[1]`). **Library and Special JS Features** There is no specific JavaScript library mentioned in the benchmark definition. However, the use of the spread operator (`...`) to create an array is a modern JavaScript feature introduced in ECMAScript 2015 (ES6). **Pros and Cons of Different Approaches** The two approaches being compared have different performance characteristics: * **Object lookup**: Using dot notation on an object can be faster than using indexing because it allows the browser's just-in-time (JIT) compiler to optimize the code. However, if the object is large or has many properties, this approach may lead to slower performance due to increased memory access. * **Array lookup**: Using the `find()` method with a callback function can be slower than using indexing because it requires more overhead and additional checks (e.g., checking for null or undefined values). **Other Considerations** * **Browser Optimization**: The benchmark results show that Chrome 103 on a desktop platform performs better for object lookups. This suggests that the browser has optimized its JIT compiler to take advantage of dot notation, which can lead to faster performance. * **Test Case Variability**: The test cases are relatively simple and consistent, but in real-world scenarios, you may encounter more complex and variable test cases. **Alternatives** Other alternatives for benchmarking JavaScript performance include: * Using a library like Webperf or Benchmark.js, which provide pre-built benchmarks and can help you compare the performance of different approaches. * Creating custom benchmarks using a testing framework like Jest or Mocha. * Using online platforms like jsperf or jsbench.net to run your own benchmarks.
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