Chrome extension options.js notify content_script.js of settings change

Question

What is the proper way to notify my content_script.js of a settings change?

When I write my setting to localStorage I want to do a sendMessage/sendRequest to the content script so it can apply them accordingly.

I would have to have to do options.js > background.js > content_script.js

Thoughts?

options.js

$('#add-filter-button')
    .button()
    .click(function(event) {
        event.preventDefault();
        var userFilters = new Array();
        var newFilter = $('#add-filter').val();
        if (newFilter !== undefined && newFilter.length > 0) {
            $('#filters-box').append(new Option(newFilter, newFilter));
            $('#add-filter').val('');
            $('#filters-box option').each(function() {
                userFilters.push( $(this).text() );
            });
            localStorage['userFilters'] = JSON.stringify(userFilters);
            chrome.storage.sync.set({'userFilters': userFilters});
        }
    });

content.js

chrome.storage.onChanged.addListener(function(changes, namespace) {
    for (key in changes) {
        var storageChange = changes[key];
        console.log('Storage key "%s" in namespace "%s" changed. ' +
            'Old value was "%s", new value is "%s".',
            key,
            namespace,
            storageChange.oldValue,
            storageChange.newValue);
        }
});

Answer 1

Use chrome.storage API https://developer.chrome.com/docs/extensions/reference/storage/#event-onChanged

It has an event onChanged

For example:

settings.js

chrome.storage.local.set({'value': theValue});

content.js

chrome.storage.onChanged.addListener(function(changes, namespace) {
  for (key in changes) {
    var storageChange = changes[key];
    console.log('Storage key "%s" in namespace "%s" changed. ' +
                'Old value was "%s", new value is "%s".',
                key,
                namespace,
                storageChange.oldValue,
                storageChange.newValue);
  }
});