Benchmark: String from Charcode test 4

Script Preparation code:

function randomCharCodes(n) {
  const arr = new Uint8Array(n);
  for(let i=0;i<n;i++) {
    arr[i] = ~~(Math.random()*0x100)
  }
  return arr;
}
const chars1 = randomCharCodes(1024*1024);
var chars = chars1;
function test1(arr) {
  const l = arr.length;
  var i = 0;
  var s = "";
  for(;i<l;i++){
    s+=String.fromCharCode(arr[i]);
  }
  return s;
}
function test2(arr) {
  return String.fromCharCode.apply(null, arr);
}
function test3(arr) {
  const l = arr.length;
  var i = 0;
  var a = [];
  for(;i<l;i++){
    a[i]=String.fromCharCode(arr[i]);
  }
  return a.join("");
}

Tests:

For-loop
var t1 = test1(chars);
String.fromCharCode.apply
var t2 = test2(chars);
join method
var t3 = test3(chars);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
For-loop
String.fromCharCode.apply
join method

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model gemma2:9b, generated one year ago):

LLMs can make mistakes. Check important info.

This benchmark on MeasureThat.net tests three different methods of converting an array of Unicode character codes into a single string in JavaScript.

Let's break down each approach:

**1.  `for` loop:** This classic method iterates through the array of character codes and uses `String.fromCharCode(arr[i])` to convert each code into its corresponding character, concatenating them into a final string.

* **Pros:** Simple and easy to understand. 
   * **Cons:** Can be less performant than other methods due to the overhead of repeated function calls within the loop.

**2. `String.fromCharCode.apply`:** This method utilizes the built-in `apply` function to efficiently convert an array of character codes into a string in a single operation.

* **Pros:** Potentially more performant than the `for` loop approach due to reduced function calls.
   * **Cons:** Less intuitive for beginners compared to a `for` loop.

**3. `join()` method:** This method first constructs an array of strings, each corresponding to a character code converted by `String.fromCharCode()`, and then uses the `join("")` method to concatenate those strings into a single string.

* **Pros:**  Can be efficient if used with large arrays as it avoids repeated function calls within the loop.
   * **Cons:** Creates an intermediate array, which might lead to slightly higher memory consumption compared to `apply`.

**Alternatives:**
* **Libraries like Lodash or Underscore:** These libraries often provide optimized string manipulation functions that might be faster than the built-in methods.

* **WebAssembly:** For highly performance-critical scenarios, you could consider implementing the conversion logic in WebAssembly, which can execute code significantly faster than JavaScript.

**Important Note:** The benchmark results presented are specific to a particular environment (Chrome 81 on Mac OS X 10.14.6). Performance can vary considerably depending on factors like browser, operating system, hardware, and the size of the input array. Always test benchmarks in your target environment for accurate results.

Related benchmarks:

String from Charcode test 4 (version: 0)

Comparing performance of: For-loop vs String.fromCharCode.apply vs join method

Created: 6 years ago by: Guest

Jump to the latest result

For-loop

String.fromCharCode.apply

join method

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model gemma2:9b, generated one year ago):