Question 86

A developer is creating a simple webpage with a button. When a user clicks this button
for the first time, a message is displayed.
The developer wrote the JavaScript code below, but something is missing. The
message gets displayed every time a user clicks the button, instead of just the first time.
01 function listen(event) {
02 alert ( 'Hey! I am John Doe') ;
03 button.addEventListener ('click', listen);
Which two code lines make this code work as required?
Choose 2 answers
  • Question 87

    developer has a web server running with Node.js. The command to start the web
    server is node server,js. The web server started having latency issues. Instead of a one second
    turn around for web requests, the developer now sees a five second turnaround,
    Which command can the web developer run to see what the module is doing during the
    latency period?
  • Question 88

    The developer wants to test the array shown:
    const arr = Array(5).fill(0)
    Which two tests are the most accurate for this array ?
    Choose 2 answers:
  • Question 89

    Refer to the code below:
    new Promise((resolve, reject) => {
    const fraction = Math.random();
    if( fraction >0.5) reject("fraction > 0.5, " + fraction);
    resolve(fraction);
    })
    .then(() =>console.log("resolved"))
    .catch((error) => console.error(error))
    .finally(() => console.log(" when am I called?"));

    When does Promise.finally on line 08 get called?
  • Question 90

    Refer to the code below:
    Const myFunction = arr => {
    Return arr.reduce((result, current) =>{
    Return result = current;
    }, 10};
    }
    What is the output of this function when called with an empty array ?