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obj property direct assign vs spread
(version: 0)
Comparing performance of:
direct vs spread
Created:
4 years ago
by:
Guest
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Tests:
direct
const a = { x1: 123, x2:'xxx', data: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13] } const arr = [4, 5, 6] const test = 'test' const out1 = { x1: a.x1, x2: a.x2, data: arr} const out2 = { x1: a.x1, x2: a.x2, data: test}
spread
const a = { x1: 123, x2:'xxx', data: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13] } const arr = [4, 5, 6] const test = 'test' const out1 = { ...a, data: arr} const out2 = { ...a, data: test}
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Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
direct
spread
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'd be happy to explain the benchmark. **What is being tested?** The provided JSON represents two test cases for measuring the performance of JavaScript objects in different ways. The first test case, "direct", tests assigning properties directly to an object (`const out1 = { x1: a.x1, x2: a.x2, data: arr}`), while the second test case, "spread", tests using the spread operator (`const out2 = { ...a, data: arr}`). **Options compared** The two options being compared are: 1. Direct assignment: Assigning properties directly to an object using dot notation (e.g., `out.x1 = a.x1`). 2. Spread operator: Using the spread operator (`...`) to create a new object by copying the original object's properties and adding new ones. **Pros and cons of each approach** 1. Direct assignment: * Pros: + Can be more concise and expressive in some cases. + May be faster for small objects or simple assignments. * Cons: + Can lead to shallow copies, which can be inefficient for large objects or complex data structures. + May not work correctly with certain types of properties (e.g., functions, dates). 2. Spread operator: * Pros: + Creates a deep copy of the original object, ensuring that any modifications to the copied object do not affect the original. + Can be more efficient for large objects or complex data structures. * Cons: + Can be less concise and verbose compared to direct assignment. + May require additional calculations or operations. **Library and its purpose** None of the provided benchmark tests use any external libraries. However, it's worth noting that some JavaScript engines or frameworks may provide built-in support for certain features or optimizations that can affect the performance of object assignments. **Special JS feature or syntax** The only special feature used in this benchmark is the spread operator (`...`), which was introduced in ECMAScript 2018. The spread operator allows creating a new object by copying an existing object's properties and adding new ones. **Other alternatives** There are other ways to achieve similar results as the "direct" and "spread" approaches: 1. Using object literals with `Object.assign()`: `const out1 = Object.assign({}, a);` 2. Using a library like Lodash's `_.clone()` or `_.merge()` 3. Implementing custom assignment logic using functions or other techniques. However, the benchmark is focused on measuring the performance of JavaScript objects in different ways, so these alternatives are not being tested directly.
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