Chrome Extension API Calls order and DOM Information - google-chrome-extension

Question

I'm working on an extension that is supposed to extract information from the DOM based specific classes/tags,etc, then allow the user to save the information as a CSV file.
I'm getting stuck on a couple of places and haven't been able to find answers to questions similar enough.
Where I am tripped up at is:
1) Making sure that the page has completely loaded so the chrome.tabs.query doesn't return null a couple of times before the promise actually succeeds and allows the blocksF to successfully inject. I have tried placing it within a settimeout function but the chrome api doesn't seem to work within such the function.
2) Saving the extracted information so when the user moves onto a new page, the information is still there. I'm not sure if I should use the chrome.storage api call or simply save the information as an array and keep passing it through. It's just text, so I don't believe that it should take up too much space.
Then main function of the background.js is below.
let mainfunc = chrome.tabs.onUpdated.addListener(
async(id, tab) => {
if (buttonOn == true) {
let actTab = await chrome.tabs.query({
active: true,
currentWindow: true,
status: "complete"
}).catch(console.log(console.error()));
if (!actTab) {
console.log("Could not get URL. Turn extension off and on again.");
} else {
console.log("Tab information recieved.")
};
console.log(actTab);
let blocksF = chrome.scripting.executeScript({
target: { tabId: actTab[0]['id'] },
func: createBlocks
})
.catch(console.error)
if (!blocksF) {
console.log("Something went wrong.")
} else {
console.log("Buttons have been created.")
};
/*
Adds listeners and should return value of the works array if the user chose to get the information
*/
let listenersF = chrome.scripting.executeScript({
target: { tabId: actTab[0]['id'] },
func: loadListeners
})
.catch(console.error)
if (!listenersF) {
console.log("Listeners failed to load.")
} else {
console.log("Listeners loaded successfully.")
};
console.log(listenersF)
};
});
Information from the DOM is extracted through an event listener on a div/button that is added. The event listener is added within the loadListeners function.
let workArr = document.getElementById("getInfo").addEventListener("click", () => {
let domAr = Array.from(
document.querySelectorAll(<class 1>, <class 2>),
el => {
return el.textContent
}
);
let newAr = []
for (let i = 0; i < domAr.length; i++) {
if (i % 2 == 0) {
newAr.push([domAr[i], domAr[i + 1]])
}
}
newAr.forEach((work, i) => {
let table = document.getElementById('extTable');
let row = document.createElement("tr");
row.appendChild(document.createElement("td")).textContent = work[0];
row.appendChild(document.createElement("td")).textContent = work[1];
table.appendChild(row);
});
return newAr
I've been stuck on this for a couple of weeks now. Any help would be appreciated. Thank you!

Answer 1

There are several issues.
chrome methods return a Promise in MV3 so you need to await it or chain on it via then.
tabs.onUpdated listener's parameters are different. The second one is a change info which you can check for status instead of polling the active tab, moreover the update may happen while the tab is inactive.
catch(console.log(console.error())) doesn't do anything useful because it immediately calls these two functions so it's equivalent to catch(undefined)
Using return newArr inside a DOM event listener doesn't do anything useful because the caller of this listener is the internal DOM event dispatcher which doesn't use the returned value. Instead, your injected func should return a Promise and call resolve inside the listener when done. This requires Chrome 98 which added support for resolving Promise returned by the injected function.
chrome.tabs.onUpdated.addListener(onTabUpdated);
async function onTabUpdated(tabId, info, tab) {
if (info.status === 'complete' &&
/^https?:\/\/(www\.)?example\.com\//.test(tab.url) &&
await exec(tabId, createBlocks)) {
const [{result}] = await exec(tabId, loadListeners);
console.log(result);
// here you can save it in chrome.storage if necessary
}
}
function exec(tabId, func) {
// console.error returns `undefined` so we don't need try/catch,
// because executeScript is always an array of objects on success
return chrome.scripting.executeScript({target: {tabId}, func})
.catch(console.error);
}
function loadListeners() {
return new Promise(resolve => {
document.getElementById('getInfo').addEventListener('click', () => {
const result = [];
// ...add items to result
resolve(result);
});
});
}