mondo-script-refactor.js

javascript:(
    () => {
        'use strict';

        const getLastUpdate = (domObj) => {
            return domObj.querySelector(".contributors-sub time").dateTime;
        };

        const isOlderJapaneseArticle = (jaLastMod, enLastMod) => {
            return Date.parse(jaLastMod) - Date.parse(enLastMod) < 0;
        };

        const renderMessages = (messages) => {
            const article = document.querySelector('#wikiArticle');
            messages.forEach((message) => article.insertBefore(message));
        }

        // fetchで英語版MDNを取得
        fetch(`https://developer.mozilla.org/${location.pathname.replace(/ja/, 'en-US')}/`)
            .then((response) => {
                console.log(response);
                return response.text();
            })
            .then((resText) => {
                const parser = new DOMParser();
                const enLastMod = getLastUpdate(parser.parseFromString(resText, "text/html"));
                const jaLastMod = getLastUpdate(document);

                let message = 'この情報は最新です☺';
                let updated = '';

                if (isOlderJapaneseArticle(jaLastMod, enLastMod)) {
                    message = '日本語の情報が古いです。';
                    updated = `en: ${enLastMod}, ja: ${jaLastMod}`;
                }

                renderMessages([message, updated]);
            });
    }
)();