Benchmark: Object.assign vs Array for

Tests:

Object.assign
const obj1 = {"a": 1, "b": 1, "c": 1, "d": 1, "e": 1, "f": 1, "g": 1, "h": 1, "i": 1, "j": 1, "k": 1, "l": 1, "m": 1, "n": 1}; const obj2 = {"o": 1, "p": 1, "q": 1, "r": 1, "s": 1, "t": 1, "u": 1, "v": 1, "w": 1, "x": 1, "y": 1, "z": 1, "*": 1, "-": 1}; Object.assign(obj1, obj2);
Array for
const obj1 = {"a": 1, "b": 1, "c": 1, "d": 1, "e": 1, "f": 1, "g": 1, "h": 1, "i": 1, "j": 1, "k": 1, "l": 1, "m": 1, "n": 1}; const arr2 = ["o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "*", "-"]; for (let i = 0; i <= arr2.length; i++) { obj1[arr2[i]] = 1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
Array for

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

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Let's dive into the world of JavaScript microbenchmarks.

**Benchmark Definition**

The benchmark is designed to compare two approaches for assigning properties to an object: using `Object.assign()` and using a loop with an array.

**Options Compared**

Two options are being compared:

1. **`Object.assign()`**: This method takes two or more objects as arguments and assigns the properties from those objects to a target object.
2. **Loop with an array**: This approach uses a loop to iterate over each property in an array, assigning values to corresponding properties on an object.

**Pros and Cons**

**`Object.assign()`**:

Pros:

* Concise and expressive syntax
* Efficient, as it only iterates over the keys of the source objects
* Wide support across browsers and platforms

Cons:

* Can be less efficient in certain scenarios due to its method call overhead
* May not work correctly with non-object values (e.g., null, undefined)

**Loop with an array**:

Pros:

* More control over the assignment process (e.g., skipping certain keys)
* Can be more efficient for large datasets or when assigning multiple values at once

Cons:

* More verbose syntax
* Requires manual management of loops and indexing
* May be less readable or maintainable

**Other Considerations**

* **Nullish coalescing operator (`??`)**: Although not explicitly used in this benchmark, the nullish coalescing operator is a relatively new JavaScript feature that can simplify certain assignment scenarios. Its introduction might impact performance and readability.
* **Browser support**: The benchmark uses Chrome 69 as the test browser. Other browsers may exhibit different performance characteristics or behaviors.

**Library**

There are no explicit libraries used in this benchmark.

**Special JS Feature/Syntax**

The only special feature used is the nullish coalescing operator (`??`), although not explicitly implemented here, it's worth noting that some modern JavaScript engines and transpilers might optimize similar expressions.

**Alternatives**

Other approaches for assigning properties to an object include:

1. **Using `for...in` loops**: Similar to the loop with an array approach, but uses a built-in loop construct.
2. **Using `Object.keys()` and `forEach()`**: Another iterative approach using built-in methods to iterate over keys.
3. **Using `Map` objects or `Set`s**: For large datasets or when assigning multiple values at once.

Each of these alternatives has its own trade-offs in terms of readability, performance, and maintainability.

Related benchmarks:

Object.assign vs Array for (version: 0)

Comparing performance of: Object.assign vs Array for

Created: 7 years ago by: Guest

Jump to the latest result

Object.assign

Array for

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):