wait for a function to complete in JavaScript

Question

In the below code, the problem is that console.log() is executed while the uploading is still in process. I want it to wait until upload is completed.

function upload(){
//firebase functions to upload file
}

function submit(){
upload();
console.log("completed");
}

Answer 1

if i remember correctly firebase function like set return a Promise
so you can easily use async await

function upload(){
return firebase.database().ref().set();
}

async function submit(){
await upload();
console.log('done');
}

Answer 2

if put() return a promise, you can simple return them.
return task;

if not, this is what i come up with, assuming function complete() are called after the upload are finished.
https://code.sololearn.com/WFpO45xJWld7/?ref=app

but you can see what i'm doing. wrap them in Promise, then call resolve() when its done or call reject() if error occur.

Answer 3

Taste it is giving error

Uncaught (in promise)
Reference.set failed:Was called with 0 arguments. Expects at least 1.

Answer 4

its an error from the send data function.
may i see the upload code ? you can remove the auth info if there's any

Answer 5

Sure Taste
Ignore some errors which might be because I had removed some lines of codes. But you can still get the logic.

https://code.sololearn.com/W7p3UEuIJ1E5/?ref=app

Answer 6

what put() do ? i cant find it in the doc
https://firebase.google.com/docs/reference/js/firebase.database.Reference.html

Answer 7

Taste thanks.
Also is my way of doing captcha verification correct ?

Answer 8

you can follow the instruction here
https://developers.google.com/recaptcha/docs/v3

Answer 9

Taste I have used recaptcha v2. The link is about v3. In the js file I have used
following code to verify recaptcha. But on internet it is given that this is only doing client side verification and not verifying using Google's server.

var response = grecaptcha.getResponse();
if(response.length == 0)
{
//reCaptcha not verified
alert("please verify you are human !");
return false;
}
else{
// execute code
}

Answer 10

btw getResponse only return a token, you'll need to do an api request with the token you're recieved
the response will always be recieved even if the captcha failed so using response.length == 0 will always false (except google is down or something). you can use .success from the response to see if it failed or not.
https://developers.google.com/recaptcha/docs/verify

Answer 11

Taste the code is working in my case and when I am not verifying the recaptcha it is giving the alert message.

Can you send me the code/example of the server side verification as in google developer's document it is given very vaguely and I am a beginner.

Thanks !

Answer 12

depend on yoir backend languange the implementation can be different. for example in node using request package

request.post({url:"https://www.google.com/recaptcha/api/siteverify",form:{secret: secret_key,response:req.body.token,remoteip:req.connection.remoteAddress}}, (error, response,body)=>{
let result= JSON.parse(body);
if(result.status){
//verified and process
}else{
//failed
}
});

it may be possible using ajax in browser, but it'll expose your secret key which is never good