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str += vs join
(version: 0)
Benchmark.js
simple test of concat strings
Comparing performance of:
str array vs str string
Created:
5 years ago
by:
Guest
Go to the latest result
Tests:
str array
var str =["hallo"]; str.push("world"); str.join("")
str string
var str ="hallo"; str += " world";
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
str array
str string
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
4 months ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/147.0.0.0 Safari/537.36 Edg/147.0.0.0
Browser/OS:
Chrome 147 on Windows
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=628372" width="100%" height="500px"></iframe>
str string
159.7M/s
str array
20.3M/s
View exact numbers
Test name
Executions per second
✓
str string
159,669,792 Ops/sec
str array
20,329,484 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'll break down the benchmark and explain what's being tested, compared, and the pros/cons of each approach. **Benchmark Overview** The MeasureThat.net benchmark tests two different ways to concatenate strings in JavaScript: using the `+=` operator and using the `join()` method. **Test Cases** There are two test cases: 1. **"str array"`**: This test case creates an array called `str` and pushes a string "world" onto it. It then calls the `join()` method on the array to concatenate all its elements into a single string. 2. **"str string"`**: This test case assigns a string "hallo" directly to the variable `str`. It then uses the `+=` operator to append another string " world" to the existing value of `str`. **Comparison** The benchmark compares the performance of these two approaches: * Using the `+=` operator to concatenate strings * Using the `join()` method to concatenate an array of strings **Pros and Cons of Each Approach** ### **+= Operator** Pros: * Simple and straightforward way to concatenate strings * Fast and efficient for small to medium-sized strings Cons: * Creates a new string object in memory on each iteration, leading to increased memory usage * Can be slower than other methods for large strings due to the creation of intermediate objects * Does not handle edge cases such as null or undefined values well ### **join() Method** Pros: * Efficient and fast way to concatenate arrays of strings * Handles edge cases such as null or undefined values by ignoring them * Can be faster than `+=` for large strings due to the use of a single buffer Cons: * Requires an array of strings, which may not always be convenient or necessary * May have performance overhead due to the creation and manipulation of the internal buffers used by the `join()` method **Other Considerations** Both approaches can be affected by various factors such as: * The size and complexity of the string being concatenated * The type and number of intermediate objects created during concatenation * The specific JavaScript engine and browser being used, which may optimize or implement `+=` differently than others. **Library Used** None of the benchmark test cases explicitly use any third-party libraries. However, it's worth noting that some browsers' built-in string manipulation functions may be implemented using external libraries or optimized with additional compiler optimizations. **Special JavaScript Features/Syntax** There are no special JavaScript features or syntax used in these test cases beyond standard ECMAScript syntax and the `+=` operator. **Alternatives** If you need to benchmark other ways of concatenating strings, you might consider testing: * Using template literals (e.g., `${expression}`) for string interpolation * Utilizing the `String.prototype.concat()` method or the `+` operator with multiple arguments * Investigating the performance of concatenating strings using arrays or buffers
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Javascript 'concat()' vs '+'
string concat + join vs unshift + join
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