Benchmark: Reduce v Filter - MeasureThat.net

Script Preparation code:

var voters = [
  { name: "Bob", age: 30, voted: true },
  { name: "Jake", age: 32, voted: true },
  { name: "Kate", age: 25, voted: false },
  { name: "Sam", age: 20, voted: false },
  { name: "Phil", age: 21, voted: true },
  { name: "Ed", age: 55, voted: true },
  { name: "Tami", age: 54, voted: true },
  { name: "Mary", age: 31, voted: false },
  { name: "Becky", age: 43, voted: false },
  { name: "Joey", age: 41, voted: true },
  { name: "Jeff", age: 30, voted: true },
  { name: "Zack", age: 19, voted: false }
];

Tests:

Reduce
voters.reduce((acc, voter) => { return voter.voted ? acc + 1 : acc; }, 0);
Filter
voters.filter(item => item.voted)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Reduce
Filter

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, the options being compared, pros and cons of each approach, and other considerations.

**Benchmark Overview**

The benchmark consists of two test cases: "Reduce" and "Filter". Both tests are designed to measure the performance of JavaScript micro-benchmarks on a specific dataset. The dataset is an array of objects representing voters with their respective votes.

**Test Case 1: Reduce**

In this test, we're reducing the `voters` array by iterating through each object in the array and adding 1 to the accumulator (`acc`) if the voter's `voted` property is true. The final result is returned as a number.

```javascript
const voters = [
  // ... (dataset)
];

console.log(voters.reduce((acc, voter) => {
  return voter.voted ? acc + 1 : acc;
}, 0));
```

**Test Case 2: Filter**

In this test, we're filtering the `voters` array to only include objects where the `voted` property is true.

```javascript
const voters = [
  // ... (dataset)
];

console.log(voters.filter(item => item.voted));
```

**Options Being Compared**

The benchmark compares two options:

1. **Reduce**: Iterates through each object in the array, adding 1 to the accumulator if `voted` is true.
2. **Filter**: Creates a new array with only the objects where `voted` is true.

**Pros and Cons of Each Approach:**

1. **Reduce**:
	* Pros:
		+ Efficient use of memory (no unnecessary copies)
		+ Can be faster for large arrays
	* Cons:
		+ May require more iterations, potentially slower for smaller arrays
2. **Filter**:
	* Pros:
		+ Faster for small arrays due to fewer iterations
		+ Easier to read and maintain
	* Cons:
		+ Creates a new array with multiple copies, potentially slower for large arrays

**Library: Lodash**

Both test cases use the `lodash` library, which is a popular JavaScript utility library. In this case, it's used for its `reduce()` and `filter()` functions.

```javascript
const _ = require('lodash');
```

The `lodash` library provides various functions for common tasks, making it easier to write efficient and readable code.

**Special JS Feature/Syntax: None**

Neither of the test cases uses any special JavaScript features or syntax beyond standard ES6+ syntax. No arrow functions, async/await, or other advanced features are employed.

**Alternatives**

If you wanted to measure the performance of these operations without using `lodash`, you could implement them manually:

```javascript
// Reduce
const reduce = (array, callback, initialValue) => {
  let result = initialValue;
  for (let i = 0; i < array.length; i++) {
    const item = array[i];
    result += callback(item, result, array);
  }
  return result;
};

// Filter
const filter = (array, callback) => {
  const result = [];
  for (let i = 0; i < array.length; i++) {
    if (callback(array[i], i, array)) {
      result.push(array[i]);
    }
  }
  return result;
};
```

Keep in mind that implementing these functions manually would likely be less efficient and more error-prone than using the `lodash` library.

This explanation should provide a clear understanding of what's being tested and compared in the benchmark.

Related benchmarks:

Reduce v Filter (version: 0)

Comparing performance of: Reduce vs Filter

Created: 3 years ago by: Guest

Jump to the latest result

Reduce

Filter

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):