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.map and .forEach
(version: 0)
Comparing performance of:
.map() vs .forEach()
Created:
3 years ago
by:
Guest
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Tests:
.map()
const a = Array.from({length: 1000000}, (_, i) => i) let total = 0; a.map(v => i += v); console.debug('.map() i=', i)
.forEach()
const a = Array.from({length: 1000000}, (_, i) => i) let total = 0; a.forEach(v => i += v); console.debug('.map() i=', i)
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
.map()
.forEach()
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Measuring JavaScript performance is an essential task for any software engineer. The provided benchmark, "MeasureThat.net," allows users to create and run microbenchmarks using JavaScript. **What's being tested?** The provided JSON represents two test cases: `.map()` and `.forEach()`. These are both array methods in JavaScript that iterate over the elements of an array. **Options compared** In this benchmark, only two options are compared: 1. **.map()**: The `map()` method creates a new array with the results of applying a provided function to every element in the calling array. 2. **.forEach()**: The `forEach()` method executes a callback function once for each element in an array. **Pros and Cons** * **.map():** + Pros: Returns a new array, allowing for filtering or transformation without modifying the original array. This can be more memory-efficient than modifying the original array. + Cons: Creates a new array, which can lead to higher memory usage compared to `forEach()`. * **.forEach():** + Pros: Modifies the original array (in-place), which can be more efficient for large arrays where modifying the original is acceptable. + Cons: Does not return any value and modifies the original array, which may not be desirable in some cases. **Library considerations** In this benchmark, no libraries are used. However, it's worth noting that `Array.prototype.map()` and `Array.prototype.forEach()` rely on the V8 JavaScript engine (used by Chrome) to execute. **Special JS feature/syntax** The provided benchmark uses a simple script with `console.debug()` statements to display intermediate results, which is a standard way to log messages in Node.js and Chrome consoles. There are no special features or syntaxes used beyond basic JavaScript syntax. **Other alternatives** For measuring performance in JavaScript, other tools and techniques exist: * **Benchmarking frameworks**: Tools like Benchmark.js or Benchmark-Harness allow you to create more complex benchmarks with multiple test cases. * **Profiling tools**: Built-in profiling tools like the Chrome DevTools Profiler or Node.js Inspector can help identify performance bottlenecks in your code. * **Microbenchmarking libraries**: Libraries like MicroBenchmark or js-benchmark provide simple, lightweight ways to measure performance in JavaScript. In summary, this benchmark on MeasureThat.net compares the performance of two array methods: `.map()` and `.forEach()`. Understanding the pros and cons of each method can help you make informed decisions about which approach to use for your specific use case.
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