Those LinkedIn messages can become a real nuisance and there is no built-in way of removing them.

Delete LinkedIn Messages

Using Chrome

• Go to your LinkedIn messages https://www.linkedin.com/messaging
• Scroll down through your messages (adds the messages to the DOM)
• Right click, Inspect
• Go to Console tab
• Paste the script (will show later)
• Repeat as needed.

Script

/*
* Delete messages
*/
function deleteMessages() {
	let container = document.querySelector(".msg-thread.relative.display-flex artdeco-dropdown artdeco-dropdown-content");
	let items = container.querySelectorAll("artdeco-dropdown-item");
	for (let i = 0; i < items.length; i++) {
		let text = items[i].textContent.trim();
		if (text === "Delete") {
			items[i].click();		// click on delete option
			break;
		}
	}
}

/*
* Confirm delete
*/
function confirmDelete() {
	let messageModal = document.querySelector("#artdeco-modal-outlet");
	if (! messageModal) return;

	let allBtns = messageModal.querySelectorAll(".artdeco-modal .artdeco-modal__actionbar button");
	if (! allBtns) return;

	let deleteBtn = allBtns[1];			// to delete, use [1], to not delete use [0]
	if (! deleteBtn) return;

	deleteBtn.click();
}

/*
* Find the next message
*/
function findNext() {
	let elem = document.querySelector(".msg-conversations-container__conversations-list .msg-conversation-listitem");
	if (! elem) {
		return false;
	}
	elem.click();
	return true;
}

/*
* main
*/
let count = 0;
var intervalId = setInterval(function() {
	if (++ count > 100) return;			// avoid infinite loops
	if (! findNext()) return;				// find next message thread

	setTimeout(function() {
		deleteMessages();							// delete message thread
		setTimeout(function() {
			confirmDelete();						// confirm delete message thread
		}, 1200);
	}, 500);
}, 2000);

Explanation

It is accepted that the page could be changed at any time. Thus, the philosophy is to build the script as a series of simple pieces that each perform simple, discreet tasks that can be easily rebuilt.

There are 3 main tasks:

• find next message thread
• delete message thread
• confirm delete message thread

Each of these tasks is to be repeated until there are no more message threads.

Main

Clearly need to use delays. The outer loop uses setInterval, else uses setTimeout

Find Next

findNext()

Find the next message thread and, if found, click it.

Delete Messages

deleteMessages()

• Find the message thread container
• Find the drop down
• Find the Delete option
• Click it

Confirm Delete

confirmDelete()

• Find the modal
• Find the buttons
• Find the delete button
• Click it

Other

Could use arrow functions, thus

let count = 0;
var intervalId = setInterval(() => {
	if (++count > 100) return;			// avoid infinite loops
	if (! findNext()) return;				// find next message thread

	setTimeout(() => {
		deleteMessages();							// delete message thread
		setTimeout(() => {
			confirmDelete();						// confirm delete message thread
		}, 1200);
	}, 500);
}, 2000);

Promises

Could rebuild as promises, something like:

const timeOutPromise = (str) => {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve(str);
    }, 200)
  })
}
timeOutPromise('foo')
  .then((val) => {
    console.log(val);
    return timeOutPromise('bar');
  })
  .then((val) => {
    console.log(val);
    return timeOutPromise('baz');
  })
  .then((val) => {
    console.log(val);
  })
  .catch((err) => console.error(err))

Async / Await

Or better yet:

const timeOutPromise = (str) => {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve(str);
    }, 200)
  })
}
(async () => {
  try {
    let val;
    val = await timeOutPromise('foo');
    console.log(val);
    val = await timeOutPromise('bar');
    console.log(val);
    val = await timeOutPromise('baz');
    console.log(val);
  } catch (err) {
    console.error(err);
  }
})();