process.hrtime.bigint();

// Create a variable and call the  
// process.hrtime() function 
var start_time = process.hrtime.bigint(); 
  
// Print the Start time 
console.log("Start Time:", start_time); 
  
// Make the add function  
setTimeout(function () { 
  
    console.log("Execution time will be calculated...."); 
  
    // Create a variable and call the second  
    // process.hrtime() function 
    var end_time = process.hrtime.bigint(); 
  
    // Print the Execution time 
    console.log("End Time:", end_time - start_time); 
  
}, 2000); 

node index.js

Start Time: 507990695929600n
Execution time will be calculated....
End Time: 1005191900n

// Create a variable and call the  
// process.hrtime() function 
var start_time = process.hrtime.bigint(); 
  
// Print the Start time 
console.log("Start Time:", start_time); 
  
// Make the add function  
setTimeout(function () { 
  
    // Create two variable 
    var a = '45', 
        b = '40'; 
  
    // Print the Subtraction result 
    console.log("Subtraction of two number is :",  
            (a - 0) - (b - 0)); 
  
    // Create a variable and call the   
    // second process.hrtime() function 
    var end_time = process.hrtime.bigint(); 
  
    // Print the Execution time 
    console.log("End Time:", end_time - start_time); 
  
}, 1000); 

Start Time: 507818309465700n
Subtraction of two number is : 5
End Time: 1008706600n