Compare the performance of checking whether an element is in an array before pushing it, and adding elements to a set in Node.

compare.js

const {
    performance
} = require('perf_hooks');

let arrayTime = [],
    arrayLen = [],
    setTime = [],
    setLen = [];

let times = 1000


for (let i = 0; i < times; i++) {

    t0 = performance.now();

    let a = []

    for (let j = 0; j < 10000; j++) {
        let x = (Math.random() * 10000).toFixed(0);
        if (!(a.includes(x))) a.push(x)
    }

    t1 = performance.now();

    arrayTime.push((t1 - t0).toFixed(5));
    arrayLen.push(a.length)
}

let averageArrayTime = arrayTime.reduce((avg, value, _, {
    length
}) => {
    return avg + value / length;
}, 0);

let averageArraySize = arrayLen.reduce((avg, value, _, {
    length
}) => {
    return avg + value / length;
}, 0);

console.log("==============================")

console.log("ARRAY TIME: \t" + averageArrayTime.toFixed(2) + " ms");
console.log("ARRAY LEN: \t" + averageArraySize.toFixed(0) + " elements");


console.log("==============================")

for (let i = 0; i < times; i++) {

    t2 = performance.now();

    let b = new Set()

    for (let j = 0; j < 10000; j++) {
        let y = (Math.random() * 10000).toFixed(0);
        b.add(y);
    }

    t3 = performance.now();

    setTime.push((t3 - t2).toFixed(5));
    setLen.push(b.size)
};

let averageSetTime = setTime.reduce((avg, value, _, {
    length
}) => {
    return avg + value / length;
}, 0);

let averageSetSize = setLen.reduce((avg, value, _, {
    length
}) => {
    return avg + value / length;
}, 0);

console.log("SET TIME: \t" + averageSetTime.toFixed(2) + " ms");
console.log("SET LEN: \t" + averageSetSize.toFixed(0) + " elements");

console.log("==============================")