Blocking event loop in nodejs

main.js

function blockForSeconds(seconds) {
    const startTime = Date.now();
    let endTime = startTime;
    while (endTime - startTime < seconds * 1000) {
        endTime = Date.now();
    }
}

function run() {
    const startTime = performance.now();

    setTimeout(() => {
        blockForSeconds(2);
        const endTime = performance.now();
        const executionTime = endTime - startTime;
        console.log(`1 second timeout with block for 2 seconds execution time: ${executionTime.toFixed(3)} milliseconds`);
    }, 1000);

    setTimeout(() => {
        const endTime = performance.now();
        const executionTime = endTime - startTime;
        console.log(`1.5 second timeout without block execution time: ${executionTime.toFixed(3)} milliseconds`);
    }, 1500);
}

run();

/*
 * Results:
 * 1 second timeout with block for 2 seconds execution time: 3000.030 milliseconds
 * 1.5 second timeout without block execution time: 3004.486 milliseconds
 */