Benchmark: javascript concat vs spread operator vs push2

Tests:

concat
var existed = Array.from({length:100},(_,i)=>i) var params = Array.from({length:100},(_,i)=>i) var other = existed.concat(params);
spread operator
var existed = Array.from({length:100},(_,i)=>i) var params = Array.from({length:100},(_,i)=>i) var other = [ ...existed, ...params ];
push
var existed = Array.from({length:100},(_,i)=>i) var params = Array.from({length:100},(_,i)=>i) var other = existed.push(...params);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat
spread operator
push

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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Let's break down the benchmark and explain what's being tested.

**What is being tested?**

The benchmark measures the performance of three different ways to concatenate arrays in JavaScript:

1. `concat()`: Using the `concat()` method to combine two arrays.
2. Spread operator (`...`): Using the spread operator to combine two arrays.
3. `push(...)` : Using the `push()` method with an array of arguments (`...params`) to add elements to an existing array.

**Options compared:**

Each test case compares the performance of one specific approach (concat, spread operator, or push) versus another. For example:

* The "concat" test case measures the performance of `existed.concat(params)` against two other approaches.
* The "spread operator" test case measures the performance of `[...existed, ...params]` against two other approaches.

**Pros and cons of each approach:**

1. **concat()**: This method is widely supported and understood in JavaScript. However, it can be slower than the spread operator or push methods because it creates a new array object.
2. **Spread operator (`...`)**: The spread operator is a modern feature that has become increasingly popular in recent years. It's often faster than `concat()` but may not work in older browsers.
3. **push(...)** : This method is also known as "rest parameter" and was introduced in ECMAScript 2015 (ES6). It can be slower than the spread operator because it needs to parse and execute a function call.

**Library:**

There is no explicit library mentioned in the benchmark definition or individual test cases. However, some libraries like Lodash may provide implementations of these methods that could affect performance.

**Special JS feature/syntax:**

The benchmark uses modern JavaScript features such as:

* Arrow functions (`=>`)
* Destructuring assignment ( `_i` in `Array.from({length:100},(_,i)=>i)` )
* Rest parameters ( `...params` in `[...existed, ...params]` )

These features are not included in older browsers that don't support ES6+, so the benchmark only provides results for modern browsers.

**Other alternatives:**

Other ways to concatenate arrays in JavaScript include:

* Loops (e.g., using `for` loops)
* Array methods like `slice()` and `splice()`
* Libraries like Lodash, which provide various array utilities

However, these approaches are not being tested in this benchmark.

Related benchmarks:

javascript concat vs spread operator vs push2 (version: 0)

javascript concat vs spread operator vs push

Comparing performance of: concat vs spread operator vs push

Created: 3 years ago by: Guest

Jump to the latest result

concat

spread operator

push

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):