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Snake Verde
Snake Verde

Reputation: 634

Converting process.hrtime() to milliseconds

I have existing code that does the following use of hrtime

before = process.hrtime()

// stuff happens...

after = process.hrtime(before)

latency = (after[0] * 1000000000 + after[1]) / 1000000;

What unit is latency above?

Upvotes: 1

Views: 4874

Answers (1)

Snake Verde
Snake Verde

Reputation: 634

Turns out the above is in fact milliseconds. Since setTimeout takes the delay value in milliseconds, it's easy to validate my hrtime juggling:

const times = []
const delays = [1, 10, 100, 1000, 1001, 1100];

function sleep(ms) {
    return new Promise((res) => {
        setTimeout(res, ms);
    });
}

async function main() {
    for (let ms of delays) {
        const ping = process.hrtime();
        await sleep(ms);
        const pong = process.hrtime(ping);
        const latency = (pong[0] * 1000000000 + pong[1]) / 1000000;
        times.push(latency);
    }

    console.log(times);
    // >>> [2.031091, 11.623596, 101.971041, 1000.554953, 1001.192077, 1104.29338]
}

main();

Upvotes: 4

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