Puppeteer pass function to evaluate. How to pass a function in Puppeteers .

Puppeteer pass function to evaluate evaluate, e. resolve(42); }`); (puppeteer will call . $(". const selector = '#someSelector'; // 2. Many people think eval is evil, maybe there is a better way, but at least it's a possible workaround. evaluate() is akin to opening Dev tools and writing set_calendar_date('1') there directly. I pass in an variable array that I would like to use to retrieve links from these sections in a drop down. The function you provide as the first argument will be In Puppeteer, when you're passing a variable into the page. const puppeteer=require("puppeteer"); (async Puppeteer evaluate function on load to show alert. you're not passing in a function but the result of the function, which is a boolean. evaluate(async => { await new Promise You can call EvaluateFunctionAsync and pass that function as string. selG is defined into the script you used to launch Puppeteer but the function you pass to page. evaluate() method with our expert guide. Pass a function inside page. log works, but inside the Chrome console and not the Puppeteer one. Puppeteer can't do this with nested ElementHandles, as of the time of writing. evaluate() this should work as well. evaluate of puppeter script. Since you're passing usedLicenses as an argument to evaluate(), you can access it inside the evaluate function directly by referencing it within the function's scope. I am using the evaluate function to return links within a drop down in our application. What you need to do is to create a Promise yourself and tell it to resolve once you have the array ready. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company I’m trying check if elements are available on a page from within a function, if the element is on the page, good, continue with the code, if not, Puppeteer: use function inside page. evaluate(() => { return Array. querySelectorAll(selector)) within the page and passes it as the first argument to pageFunction . Here’s how you can pass the I am trying to pass my custom object to page. evaluate) Update for version 1. It is returning undefined - which according to the docs I think is for a good reason (non-serializable). evaluate(), but you can call another special method (page. If you want to reuse code you can create functions on the browser side using evaluate: His await function serpDesc would need to be contained in an async function. evaluate? 2 Puppeteer: How to evaluate an XPath with a Parameter. multiplePositionsPerJob is a function that I've referenced with require in the file. To make function see vars from test context, you should pass them as a function argument. js context). I've seen people stringifying the function to pass it to puppeteer to make it work, so in your case I'd do this using eval. I'm getting multiple errors with page. You can pass a string instead of a function (although functions are recommended as they are easier to page. querySelectorAll("ul. evaluate() is not working. About; The solution that worked for me was to pass a string to evaluate rather than a function: Change: const dados = {name: 'foo', year: 1} await page. In the provided Puppeteer script, attempts to pass the variable evalVar into the evaluation function links are unsuccessful, resulting in the variable being undefined when accessed within the function. I'm using a nice logging library in node, which writes a log message with a simple logger. In function . Selector. log(result); // 123 Enable stealth mode (via puppeteer-extra-plugin-stealth) Randomize User-agent or Set a valid one (via random-useragent) Randomize Viewport size; Skip images/styles/fonts loading for better performance; Pass "WebDriver check" Pass "Chrome check" Pass "Notifications check" Pass "Plugins check" Pass "Languages check" Link to full code is here Importing a long JS function from a different file: let startTheShow = require('. 1 Puppeteer: How to evaluate xpath with document. appendFileSync with that: You are not returning any data from the page. I want to pass the result of that function into page. evaluate() you're switching the context from node puppeteer to browser, so you have to use JS native functions like click: document. Because of that, if you want to use an outside variable (a selector, for example) inside the function, you have to pass that variable as an argument to evaluate: In order to make sourceURL comments possible, this patch: - removes wrapping of the client function into `Promise. Consider the following example: I'm trying to render a page using puppeteer, extract the name of a dynamic javascript variable on the page, and return the variable as an object. stringify) and passed to your function in Node. Right not, it it not taking any arguments. In fact this is the method signature: page. evaluate() run in the browser's context which is not the context of where anum and articleHTML are defined (the node. If the function passed to page. Here is a working snippet, don't hesitate to pass {headless: false} to puppeteer. EvaluateFunctionAsync(@"async The issue is that # is a special character in URLs. So imports won't work in this context, at least not how you're attempting it. evaluate? 21. evaluate(() => new Promise(resolve => { // do all kind of asynchronous actions resolve(123); })); console. exposeFunction. evaluateHandle() and you want to get the console. The code inside page. How c I need to use a function inside page. another-element") awai page. I want to pass the existing logger object that I I've already tried everything mentioned in Error: Evaluation Failed: ReferenceError: util is not defined and How to pass required module object to puppeteer page. As a result, it doesn’t have access to variables defined in the parent scope. js Skip to main content. close(). To achieve this, it's essential to understand the correct method of passing variables into the page. Commented May 15, The page context that Puppeteer spawns (in its virtual browser) is not the same as the Node context that you write the implementation code in. Evaluate Function: Within page. log(await page. evaluate: You can pass a function that returns a Promise to the page. return value from puppeteer page. Which I believe is some sort of serialization and deserialization. evaluate fails is because the function is evaluated in a different context and the current scope (where createHdpiCanvas is available outside of the function) is lost. evaluate in puppeteer, in order to get the all gages of a gallery. Nodejs/Puppeteer - How to use page Puppeteer: pass variable in . As you may have figured it out already, the reason why page. Evaluate is called from File A where pageFunction is Function and args is params that can be passed to that function. evaluate() or page. from(document. evaluate Whatever you get from await page. Inside the second function I'm trying to console log the value of value but I get . Works quite fast compared to what Puppeteer does. evaluate to the outer scope. I am scraping data from a webpage, pagination also works. Function argument of page. How can I pass a string in and have that string be available inside of my page. Puppeteer - How to evaluate XPath which returns text? 1. You can pass a string One glitch I ran into that was non-obvious to me: It looks like Promise. exposeFunction() produce unhandled promise rejections; How to pass a function in Puppeteers . Reload to refresh your session. I'm trying to require a function from a different file into my evaluate callback, however the function never fires and causes evaluate to fail. querySelector("#list") 500 times. evaluate returns a non-Serializable value, then page. While checking the code for elementHandle. debug("Message") method. log as a trigger here is a strange choice. const title = await page . evaluate and page. evaluate for repository readability I think for smaller projects the simplest and best option is to just re-declare the objects/functions in the puppeteer context. Puppeteer - variable not getting passed in the evaluate function. In the latest version args has been replaced with _args. Hot Network Questions Alexander's dictum If you're using a transpiler like babel you might need to pass the function as a string to page. I'm using Puppeteer. So, with that encoding, your URL parameter would be selector=%23hplogo. evaluate is essentially run inside of Chrome's DevTools console, or in the same context you'd be in if you were to do so. js script scope. The "main" function receiving the page and doing page. Try this: A better puppeteer evaluate For that reason I published a little library(my first) that lets me do just that: Aptly named puppeteer-evaluate2, it allows me to write my puppeteer callback code like any other JavaScript code, where closures/imports are In Puppeteer you can evaluate async functions: await page. In both examples I pass the "pageFunction" as parameter to both methods. To return the data you have to use the return statement or use the short syntax (as explained below): console. How to pass a function in Puppeteers . js context, including any Evaluation failed: TypeError: Converting circular structure to JSON\n at JSON. evaluate should accept the arguments which you are passing. Quote from the docs: Use the EvaluateFunctionAsync method in PuppeteerSharp package in your next Puppeteer-sharp project with LambdaTest Automation Testing Advisor. evaluate(), puppeteer sends function code to the browser as a string and browser compiles it and execute in the browser context, without access to the puppeteer context, so you need to transfer the argument number explicitly. How are you sure? If you're verifying the form's presence by looking at the developer tools, that's no guarantee that the element wasn't added dynamically via JS after the page. But what is a page function in puppeteer? Edit: I should add that the following passage is given in the documentation but I don't understand what it means: pageFunction <function|string> Function to be evaluated in the page context. evaluate() Functions. How can I pass an existing object into Puppeteer's page. read the passed data const lastUpdate = await page. For each tr, there is position, title, URL. Modified 1 year, 9 months ago. evaluate with puppeteer. When sending a string instead of the function, the prints do print the string itself, and not null. evaluate((selector) => { const tds = Array. Learn how to use Puppeteer's evaluate function to pass objects and execute scripts in the browser context. 1 I am a newbie in puppeteer and I can't understand why the following code cannot work. If you want a "tricky" solution you cant try exposeFunction but usually is not a good way. Returns: Promise<HandleFor<Awaited<ReturnType<Func>>>> Remarks . So when you are using page. Evaluation failed: ReferenceError: multiplePositionsPerJob is not defined. If this still does not solve your problem, then you probably want to share all context at same scope. Alternatively, you can specify the selector type using a prefix. I obviously don't want to have a bunch of functions with the selectors hard coded I want to pass it in to the page evaluate. evaluate(), you should include it as an additional parameter. evaluate() is a method that allows you to execute JavaScript code in the context of the page. How to use Puppeteer’s page. It states: pageFunction <function|string> Function to be evaluated in the page context. js environment to the browser context. Error: Evaluation failed: ReferenceError: value is not defined My code bellow. calls because they thought they had to. This is particularly useful for interacting with the DOM, performing calculations, or manipulating data directly within the browser environment. dgControl_list>li img. This issue is specifically with elementHandle. js'); And then trying to use that function on the page. 2 Platform / OS version: Windows 10, Node 8. evaluate? 2. evaluate() method? How can I dynamically inject functions to evaluate using How to use imported function inside page. This means that if you have a 30 second timeout in waitForEvent then your puppeteer script will run for at least 30 seconds while it waits for the timeout promise to resolve even if the event fired. and. toString() on your function to get the source, which might contain references to helpers used by babel, which aren't present in the page context) Is it possible to pass a function to Puppeteer's page. Undefined Variables Contribute to puppeteer/puppeteer development by creating an account on GitHub. Master puppeteer page. selector. evaluate and I don't understand why. log() text from the browser context back to node, use the following code and make sure to set the listener before any console. How to await an async function evaluation in PuppeteerSharp. evaluate() called on them) are followed to the DOM node in the browser that they represent, and that DOM node is what your evaluate's callback is invoked with. click(). Code within page. var result = await page. evaluateHandle is that evaluateHandle page. Promising an async function. Wherever he has his await page. But it doesn't work. If the function passed to the page. using arrow function into the return block of page. exposeFunction but that seems to be for an anonymous function that is created inline. evaluate in Puppeteer with Jest? 2. src) })) Explanation: Arrow function You signed in with another tab or window. evaluate, The function setValue receives a value and returns a function. So, here is how I solve it. evaluate isn't a part of you code, and you can't call a function of your code from it. You would use it like this: Hi I am working on a web scraping script, and I have a function that currently returns to me a string. In these cases, you may prefer the evaluate approach, or only partially converting the browser code to Puppeteer code on an as-needed basis for specific trusted events. evaluate` - starts to await promise via the `Runtime. evaluate(), but when I run the script it throws a following error: Error: Evaluation failed: TypeError: Cannot read property 'p1' of undefined. I have a function called getContent() which I need to pass parameters to from a foreach loop in evaluate() but if I try to pass the function using that syntax ex: page. With page. DevTools Protocol also supports transferring some additional values that are not serializable by JSON: -0, NaN, Infinity, -Infinity, As per documentation page. — this can be mitigated a bit by In Puppeteer, page. Type. (anonymous function) (puppeteer_evaluation_script:13:22)\n at puppeteer_evaluation_script:3:31 In the documentation's example, it is passing a string (which can be serialized). It can be done with a little trickery, because page. According to the Puppeteer documentation, it says:. evaluate will be executed in a browser (just as if you opened a fresh browser, pressed F12 and pasted your code in Devtools console). puppeteer evaluate functions not accepting JSHandles or ElementHandles as variables. How to use url module in puppeteer page. Trying to execute a for loop within the page. waitForFunction functions start failing wi I've had that exact problem. js and Puppeteer for the first time and can't find a way to output values from page. 14 URLs (if applicable): Node. waitForFunction() with puppeteer. I am trying to convert a function that is used in puppeteer to puppeteerSharp and i am wondering how to do it. I'd suggest taking look at the docs and the architecture. Simple easy way probably obvious to some but for those like me, I To execute JavaScript code on your puppeteer instance, you can use the provided evaluate method. 0 Platform / OS version: macOS Mojave / 10. This handle can be a JSHandle or an ElementHandle, depending on the type of object returned by the function. $ call runs. 15. Puppeteer wait for lists coming up. : await page. evaluate and elementHandle. the reason behind this is that whatever is inside page. evaluateHandle is that evaluateHandle will return the value wrapped in an in-page object. awaitPromise` if the return type of the evaluation is promise closes #118 You can only pass serializable data to the page. password, {delay: 10}); // Types faster, just like robot Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company There is a serialization process when you call a function registered with exposeFunction. What you are looking for is the page. If you want to pass a parameter to a function via the query string of the URL, it should be URL escaped with percent encoding. Note (my bold) "evaluated in the page context". The variables j and contactList do not exist in the context of the page. How do you feel about a PR? @Vandivier I'd rather not. In Puppeteer, the page. CSS selectors can be passed as-is and a Puppeteer-specific selector syntax allows quering by text, a11y role and name, and xpath and combining these queries across shadow roots. To access the variables from in-page context in puppeteer, you need to return the variables. evaluate() runs in the context of the web page puppeteer is running in, so of course it doesn't know what fs is. querySelector(selector). evaluate(pageFunction[,args]). I'm using puppeteer and node. I’m not familiar with pupeteer at all but by looking at the documentation for that function, there may be something you can try. wait for setTImeout in page. evaluate((a, b) => { // you can use `a` and `b` here }, a, b); You can read more on arguments for the method in the docs here. waitFor in puppeteer. Using page. Is there something I am doing wrong? Evaluation failed: DOMException: Failed to execute 'querySelectorAll' on 'Element': '[object Promise]' is not a valid selector. evaluate returns a Promise, the function will wait for the promise to resolve and return its value. Commented Aug 27, 2020 at 21:20. 0. exposeFunction capabilities. For this, I am using a puppeteer evaluation function, which works correctly while the file is in . If you have errors like Error: Evaluation failed: TypeError: Cannot read property 'click' of null probably the element you wanted to click isn't on I would prefer to not have to redefine each of them within page. resolve()` - stops passing `awaitPromise` parameter to `Runtime. The workaround I found is to save the arguments to a file, pass the file path to the browser, and then fetch it. It provides a powerful way to interact with the page's DOM and extract information. If you post the predicted code i can suggest you a better way. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company You can build a function where the first argument is always the JSHandle but the rest of them are values you can pass to the evaluate function. Puppeteer has to perform the translation under the hood. – Hi im learning puppeteer headless browser, but there is something that i dont understand 1) Pass the variable to the evaluate function as an argument. You have to explicitly pass the function into the context like this: I've found that it's possible to pass a variable using the page. evaluate (() => document . function waitFor(delay) { return new Promise(resolve => setTimeout How do pass arguments to a page. evaluate resolves to undefined. evaluate(pageFunction, args); So u need to so something like this: Puppeteer's evaluate function allows you to execute JavaScript code within the context of the page. But a single argument passed is not available to the pageFunction. You switched accounts on another tab or window. evaluate takes pageFunction and a list of arguments which would be passed to the pagFunction. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company how do I call a function passing the page object outside async method in puppeteer. Puppeteer returns undefined for page. I need this variable to be used inside the browser's context. Improve this answer. evaluate despite being resolved on devtools. evaluate() method? How can I dynamically inject functions to evaluate using Puppeteer? The only difference between page. js environment; you need to explicitly pass them as arguments. Any ElementHandles passed to evaluate (or have . any explanation would be appreciated. evaluate() returns. race doesn't cancel the waitForTimeout promise. This method allows you to compute MD5 hashes directly within the page context, leveraging Puppeteer's page. 5. Execute puppeteer code within a javascript function. "doesn't work" is a useless problem description; please clarify how the code fails for you. how to put a delay in this evaluate with puppeteer. I explored page. You can pass in parameters to the evaluate function to get around this. evaluate() function - Puppeteer. g. I think you'll find the answer here: How can I Puppeteer's evaluate function allows you to execute JavaScript code within the context of the page. launch({args: ['--no-sandbox', '--disable-setuid-sandbox'], Skip to main content Take a a look at the Puppeteer documentation for page. This applies to all instances of puppeteer functions operating within the context of browser. I'll add an answer to explain in detail. evaluate() function, you need to ensure that the variable is correctly referenced within the function. /scraper. In simpler terms, running page. log(evalVar); // should be defined now }, evalVar); await can only be used in async functions. I hate redefining things but it works as You should pass arguments after evaluate arrow function. evaluate() function is a versatile tool for executing JavaScript within a page's execution context. 2. 52. Pass the elementHandle to the page. stringify ()\n at window. These are parameters that you can pass from the Node. js environment, you can use the page. tweet') is an array of elementHandle. evaluae((getContent()) => it Serializable|JSHandle> Arguments to pass to pageFunction returns: < Promise < Serializable >> Promise which resolves to the return value of pageFunction This method runs Array. The function in evaluate will be evaluated in the page context Or write your async delay function similar to page. I do not understand why this is happening. evaluate() is executed in the document (browser) scope and has no access to the main script scope (including pSelector variable). To transfer any variables of main script scope to document (browser) scope, we need to add them as second, third, etc. a. Puppeteer: use function inside page. evaluate is run in the browser context, so the console. Code: // First we register our listener. It's executed in page context and page context doesn't know anything about test context. It signals to the web browser a string called a "fragment" that targets an anchor on a web page. pageFunction. If you console, it will say JShandle or ElementHandle depending on the type. the form exists in the page and i am sure. Here is a pretty simple example, and maybe somebody can see if i'm just doing something stupid here. evaluate? 0. ) is running on every DOMMutation from the puppeteer option polling: "mutation". As moment is a function and a function cannot be serialized you cannot use it that easy. Puppeteer uses DevTools Protocol, which requires you to pass a stringified function. So it could potentially run 500 times and execute const listEl = document. evaluate(): Learn how to use Puppeteer's evaluate function to pass objects and execute scripts in the browser context. like this page. exposeFunction(name, puppeteerFunction) name <string> Name of the function on the window object; puppeteerFunction <function> Callback function which will be called in Puppeteer's context. This is the function signature of puppeteer's page. Function itself has it's own scope of visibility. Question about Puppeteer xpath element evaluation. evaluate serialize a function and send it to the puppeeter browser. To achieve this, it's essential to Puppeteer: pass variable in . Quoting directly the Puppeteer docs How can I pass variable into an evaluate function that evaluates an async function using Puppeteer? Hot Network Questions Is this version of Zorn's lemma provable in ZF? My goal is to open puppeteer-chromium instance as a child process in nodejs environment and listen to all clicks that user will make in a way that these events are accessible from Is it possible to pass a function to Puppeteer's page. I can't figure out how to pass the logger object into page. Stack Overflow. – user5734311. Error: Evaluation Failed: ReferenceError: util is not defined. x and above - Jan 2020. This occurs because How can I dynamically inject functions to evaluate using Puppeteer? [duplicate] (3 answers) Passing a function like that is no problem at all. $$('. evaluate to extract any information necessary: pSelector is a variable that is defined in the Node. element") const element2=await page. How can I evaluate a page retrieved by an url form a parent page in puppeteer`s evaluate function. js module! Everything else that you write in your code is executed not in a browser but in node. Passing Puppeteer page as params in a function is not working as expected. 1 Puppeteer - How to evaluate XPath which returns text? 0 Puppeteer returning undefined (JS) using xPath. return value from puppeteer I had the same issue, Puppeteer was crashing a free-tier EC2 instance when I tried to pass ~20MB of data to evaluate(). While learning and practicing with puppeteer I run into a problem what’s happening here is that I am passing i as an argument to the function. evaluateHandle returns a Promise, the function will wait for the promise to resolve and return its value. I have a table with tr. When you call do_many_operations(elems[0]);, elems[0] is serialized (JSON. The variable passed doesn't work. Here's the stripped down version of the code : let currentPost = 1; await page. evaluate() Share. title ); This returns the document title from the puppeteer instance All I want is to be able to pass a parameterised function as a string to the page. Problem: The return value for page. querySelectorAll(selector)) I am using puppeteer and the script works fine when executing directly with node. Ask Question Asked 3 years, 5 months ago. view-source: is the place to look for statically-present elements (and when JS runs, some of those elements may be changed or removed, I want to pass the for loop variable to page. (see the docs for more information). evaluate(async => { // await some promise }); Is there an equivalent in PuppeteerSharp? Using EvaluateFunctionAsync, the task . alljobs is an array I'm trying to push objects to. evaluate() function like this: const links = await page. Does request exist there? No, it's a node. When you use evaluate, the function you pass can return There is a similar problem if you try to pass a function. ReferenceError: alljobs is not defined. evaluate() will be run in the browser, not in the Node execution context. evaluate method to run JavaScript code in the context of the page? ('puppeteer'); async function runCodeInPage() { const browser = await puppeteer. If you want to call a function from inside the evaluate function, usually (but not in this case) you can use one of this tricks: How to pass a function in Puppeteers . evaluate so I can use it in there. @MattSergejRinc it doesn't work like that - the function that you pass in is executed by the browser that Puppeteer is running, not by your script, so it doesn't have access to variables that the evaluate function is closed over. Puppeteer: How to evaluate xpath with document. I was wondering if there is a way to cache listEl So to make your code passing an argument to be written in an input element selector, your code should be like this. evaluate function as argument. Exposing is there for you if you want. js to do this. evaluate() method? The code inside page. evaluate() is isolated from the Node. Thanks a bunch! I'm getting awfully confused with all the different ways to pass parameters in puppeteer (migrating from casperjs and phantomjs), so this sure helps (I also just discovered I can invoke the eval methods directly on my JSHandle object,which will definitely help (need to build an agGrid library to manipulate agGrid objects to test with jestJS) I'm trying to do several tests with Puppeteer sharp but it's the first time that I work with it and I don't have very clear the syntax. evaluate function and call resolve inside when your script is finished. We can pass a function as an argument to the evaluate function that will be executed within the page's context. Pass a function to evaluate() in puppeteer. Func | string Steps to reproduce Tell us about your environment: Puppeteer version: 1. evaluate? I am trying to use an XPath and an external variable in Puppeteer's evaluate function, but there is a problem: if I use the evaluate function with passing in the external variable then I can't pass in the XPath, if I remove the XPath everything is fine, but I need to do it with an XPath. e. Skip to PuppeteerSharp passing parmaters to evaluateFunctionAsync() I've seen a good number of Puppeteer scripts in a state of confusion as the author tried to translate their working console code to page. To display the logs of the Chrome context inside the Puppeteer console, you can set dumpio to true in the arguments when launching a browser using Puppeteer: To parse any data from a page you would rather wait for it to load completely and then use page. evaluate() method? Why can't I access 'window' in an exposeFunction() function The page. Close Browser: Finally, close the browser with browser. js environment, which means it does not have access to variables from your Node. How to pass array and function to Page. When using Puppeteer to evaluate a page, it's often necessary to pass variables into the evaluation function for use within the page's context. . page. 4. When you use evaluate, the function you pass can return I wouldn't call resorting to evaluate a hack, since Puppeteer doesn't pretend to offer helpers for everything, but you're right that abusing console. Is it possible to pass a function to Puppeteer's page. 1. evaluate() can only return a serializable value, so it is not possible to return an element or NodeList back from the page environment using this method. I just get this error: I found something like that works for variable, but now i need to pass a function also. evaluate and instead pass this entire "package" to page. Usage. evaluate puppeteer. Modify it as below: getTextsForChildElements: async function (selector) { const data = await page. exposeFunction makes it easier to pass data back to Node from your MutationObserver or trigger a callback than console. evaluate() function allows developers to execute JavaScript within the browser context. Note that the variables must be serializable: I'm building a web scraper, which has series of function calls passing around a puppeteer page object with the css selector string, to extract that html object and apply some arbitrary modification on it, provided as a function efn. When trying to pass in a simple object into a async function that runs puppeteer, i get this error: (node:4000) UnhandledPromiseRejectionWarning: Error: Evaluation This function in serialized, and send to the headless browser, inside puppeteer. evaluate() Puppeteer evaluate function; allow to pass a parameterized funciton as a string to page. I'm abl Anything inside of page. Learn how to set up and run automated tests with code examples of EvaluateFunctionAsync method from our library. Take a look at the function itself, the selG variable doesn't exist so the let gp = document. To pass an argument to the function you provide to page. js version: v10. So how can I change my code to make this work ? – PepeW. Run Async method within puppeteer event. evaluate also can accept a string. evaluate executes in page context and is separate from the puppeteer execution environment. await page. The function page. I use exposeFunction and I need to send the full Element to my function I have a simple example: const puppeteer = require either pass only the string and object without any circular reference, or use puppeteers ElementHandle to handle the elements. I have defi Is it possible to pass a function to Puppeteer's page. evaluate method. Tried all the different ways (saving it as a function/function expression/anonymous function, with without async), nothing works. Thankfully however, Puppeteer has a way Puppeteer - failed to pass variable into an evaluate function 1 Node Js Puppeteer value is not defined in the function (page. Puppeteer: pass variable in . 8. This is called the browser context. log() calls:. Puppeteer Sharp strange behaviour. In Pupeteer, I'd like to pass an arbitrary number of ElementHandle to the method evaluate in an array: const element1=await page. – Kevin. type('input[type="email"]', loginData. You need to return something from that anonymous function, and then call fs. 15. evaluate() must be serializable. evaluate() 9. Return Types. 2. Puppeteer page. Share. evaluate not running console. You signed out in another tab or window. Code Sample. launch() if you want to see it working with your I'm working with Node. However, passing variables into this function can be tricky. However, as soon as I build the source with pkg - page. This can be useful for interacting with the DOM (Document Object Model) or extracting information Learn how to use Puppeteer's evaluate function to pass objects and execute scripts in the browser context. The primary difference between page. ; returns: <Promise> The method adds a function called name on the page's window I am trying to evaluate a function with puppeteer but the callback is never firing (i am certain the host page is working as expected). I want to run a function inside evaluate(), I'm passing it as an argument, but I'm getting 'func is not a function', what am I missing? Puppeteer version: 10. If you use page. type('input[type="password"]', loginData. Hot Network Questions Puppeteer Pass variable in . The function you pass to evaluate is not a closure. what’s happening here is that I am passing i as an argument to the function. user, {delay: 100}); // Types slower, like a user await page. launch(); By passing arguments to page. Below is the syntax for using the evaluate function: You pass arguments to the evaluate method like this: page. evaluate() 1. map((index, element) => { i want to call for each tr ". exposeFunction() states:. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company I've got a little app i've written with node. The only difference between page. evaluate call. To expose a function to the page from your Node. This function lets you run any JS function in the page context. Here is the puppeteer function(th (page){ await page. We currently rely on a generic notion of Serializable objects, and it's quite easy to predict what will safely cross the boundary and whatnot. if you look at the example I showed of casperjs, you can see there is this line where you are basically executing a function on the Using eval() or Function() constructor inside the evaluated function and transfer the function code as a string (difficult for code writing, linting etc. evaluate, I That anonymous function you pass to page. mimg"), img => img. evaluate() method. evaluate puppeteer evaluate functions not accepting JSHandles or ElementHandles as variables. Variables in page. evaluate. Edit: typo! So, I have a function that returning page that needed by next function: async function browser(){ const browser = await puppeteer. evaluate() 0. Puppeteer: How to evaluate an XPath with a context node? 1. evaluate(`async() => { return Promise. selector to query the page for. log. Puppeteer's page. The anonymous function which is the first argument to the page. waitForFunction( . I didn't see an obvious/simple way to fix this The evaluate function in Puppeteer allows us to run JavaScript code within the context of a web page. evaluateHandle. other one is the chromium browser and those contexts run in different processes and don't share memory except when you pass variables via the puppeteer api. – Passing Variables to Puppeteer's Evaluate Function. evaluate, call the md5 function to hash a string and log the result to the console. You can pass a string instead of a function Is there a way to "cache" a value in Puppeteer's browser-based functions? The callback passed to page. It can be tested on try-puppeteer, just copy and paste my code and remove the require statement. evaluate It synchronously creates the interval, and then the whole function that you pass to page. I want to implement a functionality where if a certain value is found on page it should play a music. evaluate; Functions bound with page. It always reports Pass a function to evaluate() in puppeteer. js scope (main script scope). You cannot pass a function directly into page. puppeteer evaluate functional with callback. I've run into a situation that I do not understand. evaluate() function. evaluateHandle method in Puppeteer allows you to execute a function within the context of the page and returns a handle to the result. On the node side, that object won't have a getBoundingClientRect function. Any code that you write inside of page. How would I go about this function? Meaning predicate (the function that is being sent) is being recognized as null. 0 What is the expected result? to run What happens instead? I get the er Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company I have a csv file that stores the name of JS variables that I would like to read (evaluate) once going to a site. My current implementation, which is based on Puppeteer, iterates on the csv file and stores such variable names in an array named as "variables". Conclusion Executing JavaScript within the page context while automating with Puppeteer is straightforward with the page. There are several ways to do it, but I use a wrapper called evaluate, which accepts additional parameters to pass to the function that must be evaluated on the webkit side. Description. evaluate((selector) => Also, note that the function you pass to page. js and puppeteer. Specifically, I've tried The Puppeteer Documentation for page. querySelector(selG); can't return anything. evaluate((evalVar) => { console. 5. evaluate cannot directly reference variables from the Node. exposeFunction), which expose your function as a global function (also available in as an attribute of your page window object), so you can call it when you are inside page. The evaluate function does not run when called. mbd iyhsd bldbd bakwt xgp wdkob vsz kphvxuu alw defhxk