Async-Await in a for-loop while getting data using cheerio.js

Asked Mar 27 '19 at 07:14

Active Mar 27 '19 at 07:14

Viewed 24 times

I am trying to get data using Cheerio.js, and using async/await to synchronize requests.

Here is my (pseudo)code:

for(var i=1; i<=3; i++){

rp(url)
    .then(async (html) => {
        const $ = await cheerio.load(html);
        dataItem1 = await $('input[id=data1]').val();
        console.log(dataItem1);
        await console.log("yay!" + i);
    })
    .catch((err) => {
        console.log(err);
    })
}

When I run it using node.js, I get the output as:

<required dataItem1>
Yay! 4
<required dataItem1>
Yay! 4
<required dataItem1>
Yay! 4

but what I want is

<required dataItem1>
Yay! 1
<required dataItem1>
Yay! 2
<required dataItem1>
Yay! 3

Where am I going wrong, and what changes should I make in the code to get the desired output?

asked Mar 27 '19 at 07:14

Eagle

1

Don't use `var`, especially in loops, especially when there's anything asynchronous involved - use `let` instead (and `const` whenever the variable isn't going to be reassigned) – CertainPerformance Mar 27 '19 at 07:15
@CertainPerformance Thanks! by changing it to `let`, now I don't get the order as `4,4,4`, but with 1s, 2s and 3s only. But it isn't in the order as `1,2,3`. When I run the script repeatedly, I am getting it sometimes as `3,2,1` , `2,3,1` , `3,1,2` etc. – Eagle Mar 27 '19 at 07:20
1

If you need it to be in order, `await` each Promise in the loop – CertainPerformance Mar 27 '19 at 07:21
1

eg `await rp(url)...` – CertainPerformance Mar 27 '19 at 07:25
@CertainPerformance By adding `await` before `rp(url)`, it gives the error as `SyntaxError: await is only valid in async function`. – Eagle Mar 27 '19 at 07:29
Sounds like the containing function isn't `async`. – CertainPerformance Mar 27 '19 at 07:30
Yes! Thanks a lot @CertainPerformance it worked! I was stuck on this problem for quite a lot of time... – Eagle Mar 27 '19 at 07:32

Async-Await in a for-loop while getting data using cheerio.js

0 Answers0