Firefox Pinned Gmail Tab.js

let prev_tab_id = {}
async function onClick(tab)
{
	try {
		let current_tab = tab.id;
		let current_window = tab.windowId;

		// Find all the gmail tabs
		var tabs = await browser.tabs.query({ windowId: current_window, url: "*://mail.google.com/*" });
		if ( tabs.length == 0 )
		{
			prev_tab_id = current_tab;
			browser.tabs.create(
			{
				url: "https://mail.google.com",
				pinned: true,
				active: true
			}
			)
		}
		else
		{
			tabs.sort((a, b) => a.index - b.index);
			for ( let tab of tabs )
			{
				if ( !tab.pinned )
					browser.tabs.update(tab.id, {pinned:true})
			}

			var currentIdx = tabs.findIndex( tab => tab.id == current_tab )
			if ( currentIdx == -1 )
			{
				prev_tab_id[current_window] = current_tab
			}
			
			try {
				var prev_tab = await browser.tabs.get( prev_tab_id[current_window] )
				tabs.push( prev_tab )
			} catch (e) {}

			var nextTabIdx = ( currentIdx + 1 ) % tabs.length
			browser.tabs.update(tabs[nextTabIdx].id, { active: true, });
		}
	}
	catch (e) { console.log(e) }
}

browser.browserAction.onClicked.addListener(onClick);