let firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar', a: 1, b: 2, c: false, d: 'hello' }
firstObject = {
firstObject,
secondObject
};
const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar', a: 1, b: 2, c: false, d: 'hello' }
Object.assign(firstObject, secondObject);
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Using the spread operator | |
Using Object.assign |
Test name | Executions per second |
---|---|
Using the spread operator | 1064076.9 Ops/sec |
Using Object.assign | 8564312.0 Ops/sec |
Let's dive into the explanation.
Benchmark Definition:
The benchmark measures the performance of two ways to merge objects in JavaScript:
...
): This method is used to expand an object into multiple arguments or properties.Object.assign()
: This method is used to copy all enumerable own properties from one or more specified source objects to a destination object.Options Compared:
The benchmark compares the performance of these two methods on a sample dataset. The dataset consists of two objects:
firstObject
with a single property sampleData
containing the string "Hello world".secondObject
with multiple properties (moreData
, a
, b
, c
, and d
) containing different data.Pros and Cons:
...
):Object.assign()
:Library/Functionality:
In this benchmark, neither library nor function is explicitly used. However, Object.assign()
is a built-in JavaScript method that merges objects.
Special JS Feature/Syntax:
There are no special JavaScript features or syntax mentioned in the benchmark.
Other Considerations:
The benchmark measures the performance of these two methods on a small dataset, which might not be representative of real-world scenarios. The results may vary depending on the size and complexity of the data being merged.
Alternatives:
For merging objects, other methods can be used:
Object.create()
: Creates a new object with the specified prototype.Object.assign()
alternatives like lodash.assign()
or util._merge()
.In general, for small datasets and simple merges, the spread operator (...
) might be sufficient. However, for larger datasets or more complex merges, Object.assign()
or other methods may provide better performance and control.