Node.js process.hrtime( ) Method

The process.hrtime() method to measure code execution time which returns an array that includes current high-resolution real-time in [seconds, nanoseconds]. We measure the code execution time by providing the time returned by the first process.hrtime() call as a parameter in the second process.hrtime() call.

The Advantage of process.hrtime() is it measures time very accurately execution time which lasts less than a millisecond.

Syntax:

process.hrtime([time])

Parameter: This method accepts a single parameter as mentioned above and described below.

• time : The time is an optional parameter that must be the result of a previous process.hrtime() call to difference with the current time.

Return Type: It returns an array of 2 ints. The 1. int contains the seconds and the 2. int the nanoseconds. These times are relative to an arbitrary time in the past, and not related to the time of day.

Example 1:

Javascript

// Implement the function..

const hrTime = process.hrtime()

// Time in millisecond...
console.log("Time in millisecond is: ", hrTime[0] * 1000 + hrTime[1] / 1000000)

Output:

Time in millisecond is:  218394926745.5

Example 2:

Javascript

// Create a variable and call the process.hrtime() function.
const start_time = process.hrtime();

// Print the Start time:
console.log("Start Time:", start_time);

// Make the add function
setTimeout(function () {

    // Create two variable
    const a = '40',
        b = '50';

    // Print the Addition result:
    console.log("Add of two number is :", (a - 0) + (b - 0));


    // Create a variable and call the second process.hrtime()
    // function and pass the start time as parameter.
    let end_time = process.hrtime(start_time);
    // Print the Execution time.
    console.log("End Time:", end_time);

}, 1000);

Output: It means 1 second and 8779100 nanoseconds from start to end time is taken.

Start Time: [ 682340, 452477300 ]
Add of two number is : 90
End Time: [ 1, 8779100 ]

Example 3:

Javascript

// Create a variable and call the process.hrtime() function.
const start_time = process.hrtime();

// Print the Start time:
console.log("Start Time:", start_time);

// Make the add function
setTimeout(function () {

    console.log("Execution time will be calculated" +
        " for printing this message....");

    // Create a variable and call the second process.hrtime()
    // function and pass the start time as.
    let end_time = process.hrtime(start_time);
    // Print the Execution time.
    console.log("End Time:", end_time);

}, 1000);

Output: It means 1 second and 10987200 nanoseconds from start to end time is taken.

Start Time: [ 682865, 516565300 ]
Execution time will be calculated for printing this message....
End Time: [ 1, 10987200 ]

Reference: https://nodejs.org/api/process.html#process_process_hrtime_time