lbry.com/web/js/emailSettings.js

lbry.emailSettingsForm = function (formSelector, tags, userAuthToken) {
    var
        form = $(formSelector),
        emailSection = form.find('.email-section'),
        tagSection = form.find('.tag-section'),
        hasError = false,
        isEmailSubmitPending = false,
        tagMap = new Map(),
        isTagSubmitPending = false;

    $.each(tags, function(tag, enabled){
        tagMap[tag] = enabled;
    });

    form.find(':input').change(submitForm);

    function submitForm() {

        form.find('.notice').hide();
        hasError = false;
        isEmailSubmitPending = true;
        isTagSubmitPending = true;
        var promiseMap = $.map(emailSection.find("input"), function (element) {
            var url = 'https://api.lbry.io/user/email/edit?auth_token=' + userAuthToken
            url = url + "&email=" + element.value + "&enabled=" + element.checked.toString();
            return fetch(url).then(function (value) {
                return value.json()
            })

        });
        //Call api for each email a user will have linked - polyfill needed for IE for Promise.all
        Promise.all(promiseMap)
            .then(function (apiValues) {
                isEmailSubmitPending = false;
                showSuccess();
            })
            .catch(function (value) {
                isEmailSubmitPending = false;
                hasError = true;
                var error = "get actual error message from value";
                emailSection.find('.notice-error').html(error).show();
            });

        //do tag edit
        var url = 'https://api.lbry.io/user/tag/edit?auth_token=' + userAuthToken
        var addTags = new Array(),
            removeTags = new Array();

        tagSection.find('input').each(function () {
            var tagName = this.value
            var enabled = this.checked
            if (enabled && !tagMap[tagName]) {
                addTags.push(tagName)
            } else if (!enabled && tagMap[tagName]) {
                removeTags.push(tagName)
            }
        });

        var hasChanges = addTags[0] || removeTags[0]
        var addTagsParam = addTags[0]
        for (var i = 1; i < addTags.length; i++) {
            hasChanges = true
            addTagsParam = addTagsParam + "," + addTags[i];
        }
        var removeTagsParam = removeTags[0]
        for (var i = 1; i < removeTags.length; i++) {
            hasChanges = true
            removeTagsParam = removeTagsParam + "," + removeTags[i];
        }
        if (addTagsParam && addTagsParam.length > 0) {
            url = url + "&add=" + addTagsParam
        }
        if (removeTagsParam && removeTagsParam.length > 0) {
            url = url + "&remove=" + removeTagsParam
        }

        if (hasChanges) {
            fetch(url).then(response => {return response.json()}
        ).
            then(jsonResponse => {
                isTagSubmitPending = false;
            if (jsonResponse.success) {
                showSuccess();
            } else {
                hasError = true;
                tagSection.find('.notice-error').html(jsonResponse.error).show();
            }
        }).
            catch(function (value) {
                isTagSubmitPending = false;
                hasError = true;
                tagSection.find('.notice-error').html(value.error).show();
            });
        } else {
            isTagSubmitPending = false;
        }
    }

    function showSuccess() {
        if (!isEmailSubmitPending && !isTagSubmitPending && !hasError)
        {
            form.find('.notice-success').show()
                // .get(0).scrollIntoView();
        }
    }

    form.show();
}