Benchmark: Array.prototype.concat vs spread operator

Tests:

Array.prototype.concat
var params = [ "hello", true, 7 ]; var other = [ 1, 2 ].slice();
spread operator
var params = [ "hello", true, 7 ] var other = [ ...params ]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator

Fastest: N/A

Slowest: N/A

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

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**Benchmark Definition**

The provided JSON defines two benchmark tests: `Array.prototype.concat vs spread operator`. The purpose of this benchmark is to compare the performance of two approaches to concatenate arrays in JavaScript:

1.  **`Array.prototype.concat()`**: This method creates a new array by copying elements from an existing array and returns it.
2.  **ES6 Spread Operator (`...`)**: Introduced in ECMAScript 2015, the spread operator allows you to expand an array into individual arguments when calling functions.

**Options Compared**

The benchmark compares the performance of these two methods:

*   `Array.prototype.concat()`
*   ES6 Spread Operator (`...`)

**Pros and Cons of Each Approach**

1.  **`Array.prototype.concat()`**:
    *   Pros:
        *   Wide browser support (backwards compatible with older browsers)
        *   Clear documentation
    *   Cons:
        *   Creates a new array, which can lead to increased memory usage
        *   Can be slower than the spread operator in some cases

2.  **ES6 Spread Operator (`...`)**:
    *   Pros:
        *   More concise and readable syntax
        *   Often faster than `concat()` because it avoids the overhead of creating a new array
    *   Cons:
        *   Limited browser support (only supported in ECMAScript 2015+ compliant browsers)
        *   Less well-documented than `concat()`

**Library Usage**

In this benchmark, there is no explicit library usage. However, some JavaScript features are used:

1.  **Arrow Functions**: Used to define the `params` array and `other` array in both benchmark definitions.
2.  **Template Literals**: Not explicitly mentioned but it's implied that you're using template literals which is widely available.

**Special JS Feature/Syntax**

The test case uses JavaScript's **"slice()" method**, a native JavaScript method for creating a shallow copy of an array. However, since `slice()` was used in the older browsers support code then even with ES6 spread operator the browser would run old code for execution because of the existing code in MeasureThat.net.

**Other Alternatives**

If you're interested in exploring alternative approaches to concatenating arrays, consider:

1.  **`Array.prototype.push()```**: While not as concise as the spread operator or `concat()`, pushing elements onto an array is another way to concatenate arrays.
2.  **`Array.prototype.splice()`**: Splicing elements into an array can also be used for concatenation, although it's generally less efficient than the other two methods.

For measuring and comparing performance in a microbenchmark like this, MeasureThat.net provides a simple and straightforward way to compare different JavaScript approaches.

Related benchmarks:

Array.prototype.concat vs spread operator (version: 0)

Compare the new ES6 spread operator with the traditional concat() method

Comparing performance of: Array.prototype.concat vs spread operator

Created: 8 years ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

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):