Benchmark: Which is more efficient .replace() or .split().map().join()

Script Preparation code:

var testString = '052768194390675213483698521470';
function fakeBin(strNums){ 
  return strNums.split("")
                .map(num => num = num < 5 ? 0 : 1)
                .join("")
}
function fakeBin2(x) {
  return x.replace(/\d/g, n => "0000011111"[n])
}
function fakeBin3(word) {
  let result = '';
  for (var i = 0; i < word.length; i++) {
    result += Number(word[i]) < 5 ? 0 : 1;
  }
  return result;
}

Tests:

splitmapjoin
fakeBin(testString)
replace
fakeBin2(testString)
for
fakeBin3(testString)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
splitmapjoin
replace
for

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.127 Safari/537.36 OPR/60.3.3004.55692

Browser/OS: Opera 60 on Linux

View result in a separate tab

for

177K/s

splitmapjoin

83K/s

replace

38K/s

View exact numbers

Test name	Executions per second
✓ for	176,775 Ops/sec
splitmapjoin	82,728 Ops/sec
replace	38,241 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation.

**Benchmark Overview**

The benchmark measures the efficiency of three different approaches for replacing or transforming a string: `String.prototype.replace()`, `Array.prototype.map()` followed by `Array.prototype.join()`, and a custom implementation using a `for` loop (`fakeBin3`). The test string is generated to contain a mix of digits, ensuring that both the replacement and transformation operations are applicable.

**Approach 1: String.prototype.replace()**

*   **Purpose:** Replaces all occurrences of one or more characters in a string with another specified character or value.
*   **Library Used:** JavaScript's built-in `String` object methods.
*   **Pros:**

*   Native, optimized for performance by the JavaScript engine.
    *   Easy to read and understand due to its simplicity and convention.
*   **Cons:**

*   May be slower than custom implementations, especially when dealing with large strings or complex patterns.
    *   Requires a string pattern to be specified.

**Approach 2: Array.prototype.map() followed by Array.prototype.join()**

*   **Purpose:** Applies a transformation function to each element of an array and returns a new array. The resulting array can then be converted back into a string using `Array.prototype.join()`.
*   **Library Used:** JavaScript's built-in `Array` object methods.
*   **Pros:**

*   More flexible than `String.prototype.replace()` when dealing with complex patterns or multiple replacements.
    *   Can handle non-string elements in the array, but may incur performance overhead due to type checking and boxing/unboxing.
*   **Cons:**

*   May be slower than custom implementations for simple replacement tasks.
    *   Requires an additional step to convert the resulting array back into a string.

**Approach 3: Custom Implementation using fakeBin3 (for loop)**

*   **Purpose:** Manually iterates through each character of the input string, applying the transformation based on a specified condition (`fakeBin3`).
*   **Library Used:** None (a custom implementation).
*   **Pros:**

*   Can be faster than `String.prototype.replace()` and the array-based approach for simple replacement tasks.
    *   Allows for fine-grained control over the transformation process, including handling non-string elements or complex patterns.
*   **Cons:**

*   More error-prone due to the need to manually handle edge cases and string manipulation.
    *   May require more code and be less readable than other approaches.

**Other Alternatives**

Some additional alternatives could include:

1.  Using `String.prototype.replace()` with a regular expression (`/\\d/g` in this case) for better performance on larger strings or complex patterns.
2.  Employing a different transformation function, such as using `Array.prototype.reduce()` instead of `Array.prototype.join()`.
3.  Leveraging modern JavaScript features like `template literals` or `Intl.NumberFormat` for more efficient and readable string manipulation.

In conclusion, the choice of approach depends on the specific requirements of the task, including performance, readability, and flexibility.

Which is more efficient .replace() or .split().map().join() (version: 1) Benchmark.js

Comparing performance of: `splitmapjoin vs replace vs for`

Created: 9 years ago by: Registered User

Go to the latest result

splitmapjoin

replace

for

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Which is more efficient .replace() or .split().map().join() (version: 1) Benchmark.js

Comparing performance of: splitmapjoin vs replace vs for

Created: 9 years ago by: Registered User

Go to the latest result

splitmapjoin

replace

for

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `splitmapjoin vs replace vs for`