How can I insert a variable into a Puppeteer selector to dynamically fetch user details?
const itemCount = await page.evaluate(ctx => {
const elem = document.querySelector(`#app > section > div:nth-child(${ctx.count}) > span`);
return elem ? elem.innerText : null;
}, { count: 2 });
The key is ensuring that your variable is interpolated correctly into the CSS selector. I encountered a similar issue recently and resolved it by carefully building the selector string using template literals. It was important to double-check that the variable had the expected value before it’s injected into the selector. Since Puppeteer runs your script within a Node.js context, small oversights in variable assignment can lead to unexpected behavior. Verifying the existence of the element through intermediate debugging logs also saved me a lot of time.
hey, try using a template string: let sel = #app > section > div:nth-child(${mycount}) > span; then use page.$(sel). its dynamic and works fine for me, just make sure your variable is set correctly.
I have encountered a similar scenario where I needed to dynamically construct selectors with Puppeteer. What worked best for me was incorporating some basic error handling right before using the selector. I would typically log the value of my variable and test the resulting selector in the browser’s console. This approach helped ensure that my variable was correctly inserted and that the element existed as expected. In addition to using template literals, considering potential discrepancies in your HTML structure and performing early validation helped me avoid runtime errors.
hey, i ran into similar issues. i found that logging the value of your var right before using it and wrapping the evaluation in a try-catch helped alot. also, double-check that the ctx var is set as expected. gives you a clear picture of where it fails.
When I started using Puppeteer to work with dynamic selectors, I found that verifying both the variable value and the resulting selector string before querying the DOM was crucial. Instead of directly passing the variable to the query, I created a small helper that checks the variable’s format and returns the correct query string. I also took advantage of page.waitForSelector to ensure that the element was actually present on the page, which helped to avoid unnecessary errors. This approach allowed me to catch issues early, saving time during debugging and resulting in much more stable code execution.