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Object assign vs spread of another object
(version: 0)
Comparing performance of:
assign one object vs spread two objects
Created:
4 years ago
by:
Guest
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Tests:
assign one object
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 10).reduce((acc, num) => { return Object.assign(acc, { [num]: num }) }, {})
spread two objects
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 10).reduce((acc, num) => { return { ...acc, ...{ [num]: num } } }, {})
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
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Test case name
Result
assign one object
spread two objects
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
**Benchmark Overview** The provided JSON represents a JavaScript microbenchmark created using MeasureThat.net. The benchmark measures the performance difference between two approaches: object assignment and spread operation of another object. **Test Cases** There are two test cases: 1. **"assign one object"`**: This test case creates an array `range` that generates numbers from 0 to 10. It then uses `reduce()` to iterate over the array, assigning each number as a property of an accumulator object. 2. **"spread two objects"`**: This test case is similar to the first one, but instead of using `Object.assign()`, it uses the spread operator (`...`) to merge the accumulator object with a new object containing the current number. **Options Compared** The benchmark compares the performance of: 1. **`Object.assign()`**: A method that copies properties from an object to another object. 2. **Spread operation (`...`)**: A syntax that merges objects by copying their enumerable own enumerable properties into a new object. **Pros and Cons** * `Object.assign()`: Pros: + Wide support across browsers + Easy to read and write * Cons: + Can be slower due to the overhead of creating a new object + Can lead to memory leaks if not used carefully * Spread operation (`...`): Pros: + Fast and efficient + Reduces memory allocation + Widely supported across browsers * Cons: + May not work as expected in older browsers or with complex objects **Library Used** In both test cases, the benchmark uses the `reduce()` method, which is a built-in JavaScript function. **Special JS Feature/ Syntax** The benchmark uses the spread operator (`...`) in one of the test cases, which is a relatively modern feature introduced in ECMAScript 2018. It's widely supported across modern browsers but may not work as expected in older browsers or with complex objects. **Alternative Approaches** Other alternatives to `Object.assign()` and spread operation could be: * Using `forEach()` instead of `reduce()` * Implementing a custom loop using `for...of` or `while` * Using a library like Lodash or Underscore.js for utility functions * Leveraging browser-specific optimizations, such as WebAssembly or SIMD instructions
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