var randomNumbers = [];
for (let i = 0; i < 2000; i++) {
randomNumbers.push(Math.random());
}
const spreadOperator = [randomNumbers];
const slice = randomNumbers.slice();
const map = randomNumbers.map(num=>num);
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Spread Operator | |
Array.prototype.slice() | |
Array.prototype.map() |
Test name | Executions per second |
---|---|
Spread Operator | 1680759.9 Ops/sec |
Array.prototype.slice() | 1725002.2 Ops/sec |
Array.prototype.map() | 295365.9 Ops/sec |
Let's break down the provided JSON and benchmark preparation code to understand what is being tested.
Benchmark Definition
The Spread Operator VS Array.prototype.slice() VS Array.prototype.map()
benchmark tests three different approaches to create a shallow copy of an array:
...
) creates a new array by copying elements from the original array.slice()
method returns a shallow copy of a portion of an array, starting from the beginning and ending at the specified index.map()
method applies a provided function to each element in the array and returns a new array with the results.Pros and Cons
map()
slice()
with a negative index)slice()
, making it easier to understand and maintain
Cons:Library Usage
None of the test cases use any external libraries, so there are no additional dependencies to consider.
Special JS Features or Syntax
Other Alternatives
For creating shallow copies of arrays, other approaches include:
Array.from()
with an iterable argumentObject.assign()
with an array as the first argumentLodash
or other utility libraries that provide a cloneDeep()
function for deep copying arraysKeep in mind that the choice of approach often depends on specific use cases, performance requirements, and personal coding style.
Benchmark Considerations
When interpreting the benchmark results:
These considerations help you make informed decisions about choosing the right approach for your specific use cases.