const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
const finalObject = {
firstObject,
secondObject
};
const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
const finalObject = Object.assign({}, firstObject, secondObject);
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
spread operator | |
object assign (plain object) |
Test name | Executions per second |
---|---|
spread operator | 748335.6 Ops/sec |
object assign (plain object) | 1124608.0 Ops/sec |
Let's dive into the benchmark and explain what's being tested.
Benchmark Definition
The benchmark compares two approaches for creating a new object by merging two existing objects: the spread operator (...
) and Object.assign()
. The test cases create two simple objects, firstObject
and secondObject
, with some sample data. Then, they define the final object that should result from merging these two objects using each approach.
Options Compared
There are two options being compared:
...
): This operator creates a new object by iterating over the properties of an existing object (in this case, firstObject
and secondObject
). It takes the property names and values from both objects and adds them to the new object.Pros and Cons
...
):Library and Purpose
There is no explicit library mentioned in the benchmark definition. However, Object.assign()
is a built-in JavaScript method that's widely supported across browsers and environments.
Special JS Feature or Syntax
The test case uses the spread operator (...
), which is a modern JavaScript feature introduced in ECMAScript 2018 (ES2018). This syntax allows for more concise object merging and other features like destructuring. Not all browsers or environments support this feature, so it's essential to consider its compatibility when using it.
Other Alternatives
If you need to merge objects without using the spread operator or Object.assign()
, you can also use other methods like:
Object.concat()
(not recommended, as it creates a new object with only the last set of properties)for...in
loops or forEach()
to iterate over the properties of both objects and add them to the new objectKeep in mind that these alternatives can be less efficient or more verbose than using the spread operator or Object.assign()
, so it's essential to evaluate their trade-offs depending on your project requirements.