Benchmark: 'concat()' vs '+' vs '+=' for strings

Script Preparation code:

var somestr = "hai!";
var result = "";

Tests:

concat()
for(i = 0; i < 1000; i++) { result = result.concat(somestr); }
plus_operator
for(i = 0; i < 1000; i++) { result = result + somestr; }
plus_eq_operator
for(i = 0; i < 1000; i++) { result += somestr; }
Array.join
var a = []; for(i = 0; i < 1000; i++) { a.push(somestr); } result = a.join('');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat()
plus_operator
plus_eq_operator
Array.join

Fastest: N/A

Slowest: N/A

Latest run results:

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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.

**Benchmark Description**

The benchmark is designed to compare the performance of three different approaches for concatenating strings in JavaScript:

1. `concat()`
2. The `+` operator (also known as string addition)
3. The `+=` operator (also known as string concatenation)

The goal is to determine which approach is the fastest.

**Options Compared**

The benchmark compares the performance of each approach on a specific input: a string literal `"hai!"`. The test case is designed to repeat this operation 1000 times, and the results are recorded in terms of the number of executions per second.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

1. `concat()`: This method is generally considered safe and efficient for concatenating strings. However, it can be slower than other approaches because it creates a new string object on each iteration.
2. The `+` operator: This method is simple to use but can be slow because it involves creating multiple intermediate string objects during the concatenation process.
3. The `+=` operator: This method is also known as "string interpolation" and is often considered faster than using `concat()` or the `+` operator because it avoids creating new strings on each iteration.

**Library**

None of these methods rely on any external libraries, so there's no additional information to provide here.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax being tested in this benchmark. The focus is solely on comparing the performance of different string concatenation approaches.

**Alternatives**

If you're interested in exploring alternative string concatenation methods, here are a few options:

1. `join()`: This method is similar to `concat()` but can be more efficient for large strings because it uses an optimized internal implementation.
2. `template literals`: Introduced in ECMAScript 2015 (ES6), template literals provide a convenient way to concatenate strings using placeholders and expression evaluation.

Overall, this benchmark provides a straightforward comparison of three common string concatenation methods in JavaScript, which can be useful for optimizing performance-critical code.

Related benchmarks:

'concat()' vs '+' vs '+=' for strings (version: 1)

Testing the performance difference between concat() and the + operator for strings in javascript

Comparing performance of: concat() vs plus_operator vs plus_eq_operator vs Array.join

Created: 7 years ago by: Registered User

Jump to the latest result

concat()

plus_operator

plus_eq_operator

Array.join

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):