Doman Code - forking

doman-code-metoda-map-a-petle-for.js

// count time needed to execute a function
// precisition is 0.0001 ms
const countTime = (func) => {
    const startTime = performance.now();
    func();
    const endTime = performance.now();
    const timeNeeded = endTime - startTime;
    console.log(`${func.name} needed ${timeNeeded.toFixed(4)} ms`);
}

const lengthOfArray = 10 ** 7;
const exampleArray = Array.from({ length: lengthOfArray }, () => Math.random().toString(36).substring(2, 12));

const standardForLoop = () => {
    const resultArrayClassicFor = [];
    for (let index = 0; index < exampleArray.length; index++) {
        const arrayElement = exampleArray[index];
        const recommendString = `Polecam ${arrayElement}`;
        resultArrayClassicFor.push(recommendString);
    }
    return resultArrayClassicFor;
}

const standardForOfLoop = () => {
    const resultArrayForOf = [];
    for (const arrayElement of exampleArray) {
        const recommendString = `Polecam ${arrayElement}`;
        resultArrayForOf.push(recommendString);
    }
    return resultArrayForOf;
}

const standardMapLoop = () => {
    const resultArrayMap = exampleArray.map((arrayElement, index, currentArray) => {
      const recommendString = `Polecam ${arrayElement}`;
      return recommendString;
    });
    return resultArrayMap;
}

const myFirstMethod = () => {
    const resultArray = Array.from(exampleArray, (element) => `Polecam ${element}`);
    return resultArray;
}

const mySecondMethod = () => {
    const resultArray = exampleArray.reduce((acc, element) => {
        acc.push(`Polecam ${element}`);
        return acc;
    }, []);
    return resultArray;
}

const main = () => {
    countTime(standardForLoop)
    countTime(standardForOfLoop);
    countTime(standardMapLoop);
    countTime(myFirstMethod);
    countTime(mySecondMethod);
}

main();

// output
// standardForLoop needed 819.9759 ms
// standardForOfLoop needed 801.9562 ms
// standardMapLoop needed 931.0525 ms
// myFirstMethod needed 865.7983 ms
// mySecondMethod needed 719.9408 ms