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assign vs set
(version: 0)
Comparing performance of:
assign vs set
Created:
5 years ago
by:
Guest
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Tests:
assign
let a = {a: 1, b:2, c:3, d: 4}; Object.assign(a, {b: 'c'})
set
let a = {a: 1, b:2, c:3, d: 4}; a.b = 'c';
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Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
assign
set
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Measuring the performance of different approaches to modifying objects in JavaScript can be a valuable exercise for understanding the language's nuances and optimizing code. **What is being tested?** The provided benchmark tests two ways to modify an object: using `Object.assign()` and assigning directly to properties (`a.b = 'c'`). The goal is to determine which approach is faster. **Options compared:** 1. **`Object.assign()`**: This method creates a new object by copying all enumerable own properties from the source object (in this case, `{b:2, c:3}`) into the target object (`a`). It returns the resulting object. 2. **Direct assignment**: Assigning directly to properties of an object using syntax like `a.b = 'c'`. **Pros and cons of each approach:** 1. **`Object.assign()`**: * Pros: More explicit, easier to read, and maintainable. It also preserves the original object's structure. * Cons: Can be slower due to the overhead of creating a new object and copying properties. Additionally, it can modify the original object if not used carefully (e.g., `const a = {a: 1, b:2}; Object.assign(a, {b:3})`). 2. **Direct assignment**: * Pros: Typically faster since it only involves assigning a new value to an existing property. * Cons: Less explicit and more prone to errors (e.g., if `b` is not present in the object, the syntax will still work, but might lead to unexpected behavior). **Library used:** None are explicitly mentioned in the provided benchmark. However, it's essential to note that `Object.assign()` relies on the ECMAScript 5 standard, which was implemented by browsers and other JavaScript engines. **Special JS feature or syntax:** There is no special JavaScript feature or syntax being tested in this benchmark. The focus is solely on comparing two common approaches to modifying objects. **Other alternatives:** 1. **Using `delete`**: You can also delete properties from an object using `delete a.b;`. However, be aware that this approach may have performance implications and is generally less recommended. 2. **Using a library or utility function**: There are libraries (e.g., `lodash`) and utility functions (e.g., `_.assignIn()`) available that provide alternative ways to modify objects. These often offer additional features, but may also introduce overhead. For this benchmark, the results indicate that direct assignment (`a.b = 'c'`) is faster than using `Object.assign()` on a desktop Chrome 84 browser running Mac OS X 10.15.4.
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