Dupe IP helper

gistfile1.txt

// ==UserScript==
// @name         Dupe review helper
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Watches out for reviews made by the same IP subnet
// @author       anevins12
// @match        https://wordpress.org/support/topic/*
// @grant        none
// ==/UserScript==

(function(isPluginReview, checkData) {
    'use strict';

    var $ = jQuery,
        pluginName,
        reviewCollection = {
            plugin: '',
            ip: 0,
            url: ''
        },
        namespace,
        matchedStoredCollection,
        identifierClass = 'wp-duplicate-review-flag',
        message,
        messageClass = 'wp-duplicate-message',
        removeData = $('<button class="wp-remove-data">🚩 Clear duplicated reviews</button>');

    if (isPluginReview($)) {
        reviewCollection.plugin = $('.bbp-breadcrumb-forum').text();
        reviewCollection.ip = $('.bbp-topic-ip').text().replace(/["'()]/g, '');
        reviewCollection.url = window.location.pathname;
        namespace = 'wp-reviewee-';
        matchedStoredCollection = JSON.parse(localStorage.getItem(namespace +  reviewCollection.ip));

        removeData
            .css({
                'fontSize': '80%',
                'position': 'relative',
                'top': '-1em'
            })
            .on('click', function() {
                var button = $(this),
                    message = $('.' + identifierClass);

                checkData(namespace, true);

                button
                    .css('border-color', 'lawngreen')
                    .html('🚩 Duplicated reviews cleared')
                    .delay(2000)
                    .fadeOut();

               if (message.length !== 0) {
                   message.remove();
               }
            });

        // If reviews have been stored
        if (checkData(namespace)) {
            $('.bbp-breadcrumb').prepend(removeData);
        }

        if (matchedStoredCollection) {
            message = $('<a class="' + messageClass + ' author-badge author-badge-plugin' + identifierClass + '" href="' + matchedStoredCollection.url + '">Duplicate review</a>');

            // If this is a new review but for the same plugin & IP
            if (matchedStoredCollection.plugin === reviewCollection.plugin &&
                matchedStoredCollection.ip === reviewCollection.ip &&
                matchedStoredCollection.url !== reviewCollection.url) {
                message.css({
                    'background': 'red',
                    'color': 'white',
                    'fontWeight': '700',
                    'fontSize': '150%',
                    'margin-top': '-5px',
                    'margin-left': '-1em',
                    'textDecoration': 'underline'
                });

                $('.bbp-topic-ip').append(message);
            }
        } else {
            localStorage.setItem(namespace + reviewCollection.ip, JSON.stringify(reviewCollection));
        }
    }

})(isPluginReview, checkData);

function isPluginReview($) {
    'use strict';

    var ratings = $('.single-topic .wporg-ratings');

    if (ratings.length !== 0) {
        return true;
    }

    return false;
}

function checkData(name, destroy) {
    /*
     * Returns truthy if is data stored
     * Destroys data if argument passed
     */

    'use strict';

    var reviewData = [],
        check = function(key) {
            if (/^/ + name) {

                reviewData.push(key);

                if (destroy) {
                    localStorage.removeItem(key);
                }
            }
        };

    Object
        .keys(localStorage)
        .forEach(function(key) {
            check(key);
        });

    if (reviewData.length > 1) {
        return true;
    } else {
        return false;
    }
}

Feedback:

• Replace the "Dupe" text, instead make it a bit more noticable, maybe inject it like the flag yo usee for authors, adding that to it with "Duplicate review" as the label and some eye-catching color might be nice, makes it faster to spot when scanning
• I'm also wondering about the lifetime of the data store, it seems like it has no limit to the lfietime, that's going to quickly become a bit of a memory hog with time consideringthe amount of reviews we receive
  perhaps introducing some kind of indicator of how much data is stored with the ability to purge it easily ?