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Array.prototype.slice vs spread operator v3
(version: 1)
Compare the new ES6 spread operator with the traditional slice() method
Comparing performance of:
Array.prototype.slice vs spread operator
Created:
11 months ago
by:
Guest
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Tests:
Array.prototype.slice
var params = [ "hello", true, 7 ]; var other = params.slice();
spread operator
var params = [ "hello", true, 7 ] var other = [ ...params ]
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
Array.prototype.slice
spread operator
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
9 months ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:141.0) Gecko/20100101 Firefox/141.0
Browser/OS:
Firefox 141 on Windows
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<iframe src="https://measurethat.net/Embed?id=614445" width="100%" height="500px"></iframe>
Test name
Executions per second
Array.prototype.slice
97551000.0 Ops/sec
spread operator
54999412.0 Ops/sec
Autogenerated LLM Summary
(model
gpt-4o-mini
, generated 11 months ago):
The benchmark defined here compares two approaches for copying arrays in JavaScript: the traditional `Array.prototype.slice()` method and the newer ES6 spread operator (`...`). ### Options Compared 1. **Array.prototype.slice() Method** - **Benchmark Definition**: `var params = [ "hello", true, 7 ]; var other = params.slice();` - **Purpose**: `slice()` creates a shallow copy of a portion of an array into a new array object. In this context, it is used without arguments, meaning it copies the entire array. 2. **Spread Operator** - **Benchmark Definition**: `var params = [ "hello", true, 7 ]; var other = [ ...params ];` - **Purpose**: The spread operator allows for expanding an iterable (like an array) into its individual elements. Here, it is used to create a new array by spreading the elements of `params`. ### Results Overview The benchmark results indicate the performance efficiency of each method in terms of executions per second: - **Spread Operator**: 433,134,496 executions per second - **Array.prototype.slice()**: 104,622,920 executions per second ### Pros and Cons #### Array.prototype.slice() **Pros:** - Works in older JavaScript environments, ensuring wider compatibility with legacy code. - Explicitly designed for array manipulation, making it clear to other developers what the intention is. **Cons:** - Generally slower compared to the spread operator based on the benchmark results. - Slightly more verbose than using the spread operator. #### Spread Operator (`...`) **Pros:** - Faster in this benchmark scenario, making it more efficient for performance-critical applications. - More concise syntax, improving code readability. - Versatile; can be used not just with arrays, but also with other iterable objects (e.g., strings, sets). **Cons:** - Requires ES6 support, which may not be available in older environments (though this concern is diminishing as modern browsers adopt ES6). - May not be as clear as `slice()` for some developers when copying arrays, since it's a more generalized syntax. ### Other Considerations - **Compatibility**: Depending on the target environment, developers might still need to use `slice()` for compatibility, particularly in older browsers or environments that do not support ES6. - **Considerations for Large Arrays**: Depending on the size of the arrays being operated on, performance differences may become pronounced, thus favoring the faster approach if significant performance improvements are needed. ### Alternatives - **Array.prototype.concat()**: Another legacy approach to create shallow copies is using `concat()` method (e.g., `[].concat(params)`), but it is also typically slower than the spread operator. - **Looping/ForEach**: Manually copying arrays with loops (e.g., using `for`, `forEach`, etc.) can also be an alternative, though it's generally more cumbersome and usually slower unless optimized. - **Object.assign or Array.from**: While `Object.assign` and `Array.from` can work for certain use cases, they may not be direct substitutes for array copying compared to `slice()` and the spread operator. In conclusion, while both methods achieve the same goal of copying an array, the choice between them can depend on factors like performance requirements, compatibility considerations, and code readability preferences.
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