@a-2-c-2-anpm/vel-fugiat-consectetur

Evaluate a script function on a page with Chrome
This module let you evaluate a script function on a page using Chrome (controlled with puppeteer) and get the return value of the evaluation in node.
Usage
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Test page</title>
</head>
<body>
<div class="content">1</div>
<div class="content">2</div>
<div class="content">3</div>
<div class="content">4</div>
</body>
</html>
const puppeteer = require('puppeteer')
const chromePageEval = require('@a-2-c-2-anpm/vel-fugiat-consectetur')
const chromeEval = chromePageEval({ puppeteer })
(async () => {
try {
const result = await chromeEval({
html: '/path/to/sample.html',
scriptFn: `
function () {
let title = document.title
let content = Array.from(document.querySelectorAll('.content'), (node) => {
return node.textContent
})
return {
title,
content
}
}
`
})
console.log(result.title)
console.log(result.content)
} catch (e) {
console.error('Error while trying to evaluate script:', e)
}
})()
Constructor options
const chromePageEval = require('@a-2-c-2-anpm/vel-fugiat-consectetur')
const chromeEval = chromePageEval({ })
Evaluate options
const puppeteer = require('puppeteer')
const chromePageEval = require('@a-2-c-2-anpm/vel-fugiat-consectetur')
const chromeEval = chromePageEval({ puppeteer })
(async () => {
const result = await chromeEval({ })
})()
html string [required] - the path to the html file to load in a Chrome page
scriptFn string [required] - the script to evaluate in the Chrome page. the script must be a function that returns a value. ex: scriptFn: 'function () { return 1 + 2}'
viewport object - object with any of the viewport options supported by puppeteer
args array - a list of custom arguments to pass to the scriptFn function. ex: args: [1, 2] and with scriptFn: function (a, b) { return a + b}' will produce 3 as result
styles array - array of css strings to insert at the beginning of page's head element. ex: styles: ['* { font-family: 'Calibri'; font-size: 16px; }']
waitForJS boolean - when true the scriptFn won't be executed until the variable specified in waitForJSVarName option is set to true in page's javscript. defaults to false
waitForJSVarName string - name of the variable that will be used as trigger of scriptFn. defaults to "CHROME_PAGE_EVAL_READY"
waitUntil string - a value that specifies when a page is considered to be loaded, for the list of all possible values and its meanings see waitUntil option in puppeteer docs. defaults to the the default value of puppeteer
timeout number - time in ms to wait for the script evaluation to complete, when the timeout is reached the evaluation is cancelled. defaults to 30000
Requirements
- Install puppeteer >= 1.0.0 with
npm install puppeteer --save in your project and pass it to @a-2-c-2-anpm/vel-fugiat-consectetur constructor function.
Caveats
- What you return in your script function (
scriptFn option) must be a serializable value in order to receive it properly, if a non serializable value is returned you will get undefined as the result.
Debugging
-
To get more information (internal debugging logs of the module) about what's happening during the evaluation on the page start your app in this way: DEBUG=@a-2-c-2-anpm/vel-fugiat-consectetur* node [your-entry-file-here].js (on Windows use set DEBUG=@a-2-c-2-anpm/vel-fugiat-consectetur* && node [your-entry-file-here].js). This will print out to the console some additional information about what's going on.
-
To see the Chrome instance created (the visible chrome window) run your app with the CHROME_PAGE_EVAL_DEBUGGING env var: CHROME_PAGE_EVAL_DEBUGGING=true node [your-entry-file-here].js (on Windows use set CHROME_PAGE_EVAL_DEBUGGING=true && node [your-entry-file-here].js).
License
See license