background.js

/*global chrome*/

// The following is needed to open option page automatically
// if the locale is not set
// https://stackoverflow.com/questions/49192636/how-can-i-open-my-options-html-currently-i-get-cannot-read-property-create-of
//
// This Js file is run in the background, see:
// https://developer.chrome.com/extensions/background_pages
chrome.runtime.onMessage.addListener(function(message) {
    switch (message.action) {
    case 'openOptionsPage':
        openOptionsPage();
        break;
    default:
        break;
    }
});

chrome.commands.onCommand.addListener(function(command) {
    if (command === 'translate-math') {
        //Send keyboard shortcut click to the current tab
        chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
            chrome.tabs.sendMessage(tabs[0].id, {'action': 'translate-math'});
        });
    }
});

/**
 * Auxiliary function to open Options page
 * using Chrome API
 *
 * @returns {undefined}
 */
function openOptionsPage() {
    chrome.runtime.openOptionsPage();
}