Benchmark: findIndex vs for loop 2

Script Preparation code:

function Xoroshiro128Plus(options) {
    let {
        state
    } = options || {};

    if (!state) {
        let time = (Date.now() | 0) >>> 0;
        state = [
            (time & ((Math.random() * 0xffffffff) | 0)) >>> 0,
            (time & ((Math.random() * 0xffffffff) | 0)) >>> 0,
            (time & ((Math.random() * 0xffffffff) | 0)) >>> 0,
            (time & ((Math.random() * 0xffffffff) | 0)) >>> 0,
        ];
    }

    this.next64 = () => xoroshiro128plus(state);
    this.getState = () => state.slice();
}

function xoroshiro128plus(state) {
    let s0 = [state[0], state[1]];
    let s1 = [state[2], state[3]];

    let result = sum64(s0, s1);

    s1 = xor64(s1, s0);
    let [a, b] = xor64(
        xor64(or64(shiftLeft64(s0, 55), shiftRight64(s0, 9)), s1),
        shiftLeft64(s1, 14),
    );
    let [c, d] = or64(shiftLeft64(s1, 36), shiftRight64(s1, 28));

    state[0] = a;
    state[1] = b;
    state[2] = c;
    state[3] = d;

    return result;

    function shiftLeft64([x, y], count) {
        // `32` case is not handled
        if (count < 32) {
            x = x << count;
            let a = (y >>> (32 - count)) & (Math.pow(2, count) - 1);
            x += a;
            return [x >>> 0, (y << count) >>> 0];
        } else {
            x = (y & (Math.pow(2, 64 - count) - 1)) << (count - 32);
            return [x >>> 0, 0];
        }
    }

    function shiftRight64([x, y], count) {
        // `32` case is not handled
        if (count < 32) {
            let a = x & (Math.pow(2, count) - 1);
            y = (y >>> count) + (a << (32 - count));
            return [x >>> count, y >>> 0];
        } else {
            let a = (x >> (count - 32)) & (Math.pow(2, 64 - count) - 1);
            x = (x >> (count - 32)) & (Math.pow(2, 64 - count) - 1);
            x = x + (a << (count - 32));
            return [0, x >>> 0];
        }
    }

    function or64([a0, a1], [b0, b1]) {
        return [(a0 | b0) >>> 0, (a1 | b1) >>> 0];
    }

    function xor64([a0, a1], [b0, b1]) {
        return [(a0 ^ b0) >>> 0, (a1 ^ b1) >>> 0];
    }

    function sum64([a0, a1], [b0, b1]) {
        let [y, overflow] = sum32(a1, b1);
        let x = (a0 + b0 + (overflow ? 1 : 0)) >>> 0;
        return [x, y];
    }

    function sum32(a, b) {
        let overflow = false;

        let max = 0xffffffff;
        max -= a;

        if (b > max) {
            overflow = true;
        }

        return [(a + b) >>> 0, overflow];
    }
}

var random = new Xoroshiro128Plus({
    state: [1292125120, -349674120, 855278889, 359289241]
});

var ELEMENTS_COUNT = 1000;
var FIELDS_COUNT = 10;

var items = [];

for (let i = 0; i < ELEMENTS_COUNT; i++) {
    var [zIndex, bits] = random.next64();

    var obj = {
        zIndex
    };

    for (let j = 1; j <= FIELDS_COUNT; j++) {
        obj[`prop${j}`] = Boolean((bits >> (j - 1)) & 1);
    }

    items.push(obj);
}

var keys = [
  "prop1",
  "prop2",
  "prop3",
  "prop4",
  "prop5",
  "prop6",
  "prop7",
  "prop8",
  "prop9",
  "prop10",
];

Tests:

findIndex
return items.findIndex(item => item.prop7)
for loop
var i = 0; for (; i < length; i++) { if (items[i].prop7) { return i; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
findIndex
for loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.55 Safari/537.36

Browser/OS: Chrome 96 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
findIndex	12678443.0 Ops/sec
for loop	4524765.5 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmarking test case on MeasureThat.net. The test compares the performance of two approaches:

1. `findIndex` method: Using the built-in `Array.prototype.findIndex()` method to find an item in the `items` array that matches the condition.
2. For loop: Implementing a manual for loop to iterate through the `items` array and return the index of the first matching element.

**Library Used**

The test case uses the Xoroshiro128Plus pseudorandom number generator, which is a widely used algorithm for generating high-quality random numbers. The library is not specifically related to the benchmarking test itself, but rather provides a random number generator that's used to populate the `items` array.

**Comparison of Approaches**

The two approaches being compared are:

1. **findIndex**: This method uses the built-in JavaScript function to find an item in the array that matches the given condition. It's a concise and efficient way to perform this operation.
2. **For Loop**: This approach involves implementing a manual for loop to iterate through the `items` array, checking each element against the condition, and returning the index of the first matching element.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **findIndex**
	* Pros:
		+ Concise and efficient.
		+ Built-in function, so it's likely to be well-optimized.
	* Cons:
		+ May not be as educational or insightful for understanding performance optimizations.
2. **For Loop**
	* Pros:
		+ Can provide insights into performance optimization techniques, such as indexing and caching.
		+ May be more educational for developers who want to understand the underlying mechanics of array iteration.
	* Cons:
		+ More verbose and less efficient than the built-in `findIndex()` method.

**Performance Considerations**

The performance results show that the `findIndex` method is significantly faster than the manual for loop approach, with a ratio of approximately 2.7:1. This is likely due to the optimized implementation of the built-in function, which can take advantage of various caching and indexing techniques.

However, it's worth noting that the performance difference may not be significant enough to justify using the `findIndex()` method in all cases. If educational value or insight into performance optimizations are important, the for loop approach may still be a good choice.

In summary, the benchmark compares two approaches to finding an item in an array: the built-in `Array.prototype.findIndex()` method and a manual for loop implementation. The results show that the `findIndex` method is significantly faster due to its optimized implementation.

Related benchmarks:

findIndex vs for loop 2 (version: 0)

Comparing performance of: findIndex vs for loop

Created: 2 years ago by: Guest

Jump to the latest result

findIndex

for loop

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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