Variable scope in async functions

Question

I am trying to access a variable that i declared inside in an async function. Like this:

exports.startTheBasketEngine = async (username, password, domainData) => {
    const parse = domainData.auctionUrl.split("-")
    var domainName = parse[0]

    const stringIsIncluded = await page.evaluate(() => {
        console.log(domainName)
     });
}

The console.log line is returning that error:

 UnhandledPromiseRejectionWarning: Error: Evaluation failed: ReferenceError: domainName is not defined

How can i resolve this problem?

Works for me locally. We need to see more code to evaluate the problem. What's in page.evaluate() ? — MauriceNino
– MauriceNino, Commented Jul 8, 2020 at 12:10
Have you tried something like this: await page.evaluate((dName) => { console.log(dName); }, domainName);? — Sebastian Kaczmarek
– Sebastian Kaczmarek, Commented Jul 8, 2020 at 12:14

Sebastian Kaczmarek · Accepted Answer · 2020-07-08 12:23:20Z

1

I assume you use Puppeteer.

According to the docs, the .evaluate() takes more arguments. All arguments, starting from the second, will be passed to the pageFunction. So try something like this:

var domainName = parse[0]

const stringIsIncluded = await page.evaluate((dName) => {
    console.log(dName);
 }, domainName);

answered Jul 8, 2020 at 12:23

Sebastian Kaczmarek

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Comments

László Szikszai · Accepted Answer · 2020-07-08 12:17:29Z

1

You should pass the value to evaluate, it is executed in a separate context, see: https://github.com/puppeteer/puppeteer/blob/main/docs/api.md#pageevaluatepagefunction-args

const stringIsIncluded = await page.evaluate((domainName) => {
    console.log(domainName)
}, domainName);

answered Jul 8, 2020 at 12:17

László Szikszai

513 bronze badges

Comments

OlgaAI · Accepted Answer · 2020-07-08 12:22:04Z

0

You have to pass your variable:

 const stringIsIncluded = await page.evaluate((domainName) => {
    console.log(domainName)
 }, domainName);

answered Jul 8, 2020 at 12:22

OlgaAI

1

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