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object.assign vs spread to create a copy
(version: 0)
Comparing performance of:
object.assign vs spread
Created:
7 years ago
by:
Guest
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Tests:
object.assign
var a = { a: 'oh', b: 'my' }; var b = Object.assign({}, a);
spread
var a = { a: 'oh', b: 'my' }; var b = { ...a };
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Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
object.assign
spread
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark definition and test cases to understand what is being tested. **Benchmark Definition** The benchmark measures the performance difference between using `Object.assign()` and the spread operator (`...`) to create a copy of an object in JavaScript. **Options Compared** Two options are compared: 1. **`Object.assign()`**: This method creates a shallow copy of an object, which means it only copies the own enumerable properties from the original object. It returns a new object with these properties. 2. **Spread Operator (`...`)**: This operator creates a new object that copies all the own enumerable properties from the original object. **Pros and Cons** * **`Object.assign()`**: + Pros: Widely supported, easy to use, and efficient for simple cases. + Cons: Can be slower than the spread operator for complex objects, as it involves more operations. * **Spread Operator (`...`)**: + Pros: Modern JavaScript feature, faster performance, and easier to read in many cases. + Cons: Requires modern browsers (Chrome 74 or higher), and its behavior can vary depending on the object's properties. **Library Used** None is explicitly mentioned. However, `Object.assign()` is a built-in method in ECMAScript. **Special JavaScript Feature or Syntax** The spread operator (`...`) is a relatively new feature introduced in ECMAScript 2018 (ES2018). It allows for creating new objects with the properties of an existing object, making it easier to clone and manipulate data. **Other Considerations** When comparing these two options, consider the following: * For simple cases, `Object.assign()` is a reliable choice. However, as the complexity of the object increases, the spread operator may be faster. * If you need to support older browsers or versions of Node.js, using `Object.assign()` might be necessary. **Other Alternatives** If you need to create a deep copy of an object (i.e., copying all its properties, including nested objects), consider using libraries like Lodash (`_.cloneDeep`) or the `JSON.parse(JSON.stringify())` method. These alternatives may provide better performance for large, complex objects. In summary, the benchmark measures the performance difference between two methods to create a copy of an object: `Object.assign()` and the spread operator. While both have their pros and cons, the spread operator is generally faster and more readable in modern JavaScript scenarios.
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