Measure Execution Time of JavaScript Code with Callbacks

javascriptnode.jsprofiling

I have a piece of JavaScript code that I am executing using the node.js interpreter.

for(var i = 1; i < LIMIT; i++) {
  var user = {
    id: i,
    name: "MongoUser [" + i + "]"
  };
  db.users.save(user, function(err, saved) {
    if(err || !saved) {
      console.log("Error");
    } else {
      console.log("Saved");
    }
  });
}

How can I measure the time taken by these database insert operations? I could compute the difference of date values after and before this piece of code but that would be incorrect because of the asynchronous nature of the code.

Best Answer

Use the Node.js console.time() and console.timeEnd():

var i;
console.time("dbsave");

for(i = 1; i < LIMIT; i++){
    db.users.save({id : i, name : "MongoUser [" + i + "]"}, end);
}

end = function(err, saved) {
    console.log(( err || !saved )?"Error":"Saved");
    if(--i === 1){
      console.timeEnd("dbsave");
    }
};

Using performance.now():

var startTime = performance.now()

doSomething()   // <---- measured code goes between startTime and endTime
    
var endTime = performance.now()

console.log(`Call to doSomething took ${endTime - startTime} milliseconds`)

In Node.js it is required to import the performance class

importing performance

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

Using console.time: (living standard)

console.time('doSomething')
    
doSomething()   // <---- The function you're measuring time for 
    
console.timeEnd('doSomething')

Note:
The string being passed to the time() and timeEnd() methods must match
(for the timer to finish as expected).

console.time() documentations:

MDN documentation

Node.js documentation

Best Answer

Related Solutions

JavaScript – How to Measure Time Taken by a Function to Execute

Using performance.now():

Using console.time: (living standard)

console.time() documentations:

Related Question

`console.time()` documentations: