In this article, we will measure the time taken by a function to execute using Javascript. To measure the time taken by a function to execute we have two methods:
Method 1: Using the performance.now() method.
The now() method of the performance interface returns a high-resolution timestamp whenever it is called during the program. The time can be measured by getting the starting time before the function and the ending time after the function and then subtracting both of them. This gives the time elapsed for the function.
Syntax:
start = performance.now(); function_to_call(); end = performance.now();
Example: This example explains the above-used approach.
html
<h1 style="color: green"> neveropen </h1> <b> How to measure time taken by a function to execute using JavaScript? </b> <p> Click on the button to measure the time taken by the function. The output would be displayed on the console. </p> <button onclick="measurePerformance()"> Click to check </button> <script type="text/javascript"> function measurePerformance() { start = performance.now(); exampleFunction(); end = performance.now(); timeTaken = end - start; console.log("Function took " + timeTaken + " milliseconds"); } function exampleFunction() { for (i = 0; i < 1000; i++) { console.log('Hello Geeks'); } } </script> |
Output:
Method 2: Using the console.time() method.
The time() and timeEnd() methods of the Console object could be used as a timer to measure the time taken between these two methods. It takes a label parameter that could be used to distinguish between multiple timers. Whenever the timeEnd() method is called, the timer is stopped and the time output is given to the console.
Syntax:
console.time('label');
function_to_call();
console.timeEnd('label');
Example: This example explains the above approach.
html
<h1 style="color: green"> neveropen </h1> <b> How to measure time taken by a function to execute using JavaScript? </b> <p> Click on the button to measure the time taken by the function. The output would be displayed on the console. </p> <button onclick="measurePerformance()"> Click to check </button> <script type="text/javascript"> function measurePerformance() { console.time('function1'); exampleFunction(); console.timeEnd('function1'); } function exampleFunction() { for(i= 0;i <1000; i++) { console.log('Hello Geeks'); } } </script> |
Output:
