Step 1: Install the module as dev dependency.

npm install functiontime --save-dev

Step 2: Require the module.

const functiontime = require("functiontime");

Step 3: Use the module.

function printNo(){
    for(let i = 0 ; i < 10000; i++){
        //logic
    }
}

functiontime(printNo);

//output printNo time: 36.413ms