main.js

// ==UserScript==
// @name         Name
// @namespace    ns
// @version      0.1
// @description  Description
// @author       Peyang
// @match        https://example.com/*
// @grant        none
// ==/UserScript==

var json = [
    {
        "name": "Alert > Body",
        "path": "^\/.*",
        "selector": "div[role=alert] > span:nth-child(2)",
        "rules": [
            {
                "properties": [],
                "replace": "We have e-mailed your password reset link!",
                "translate": "パスワードリセットリンクをメールで送信しました！"
            },
        ]
    },
    {
        "name": "Alert > Body2",
        "path": "^\/2\/.*",
        "rules": [
            {
                "properties": ["placeholder"],
                "selector": ["textbox", ]
                "translate": "ここに入力"
            },
            {
                "properties": [],
                "selector": ["div"]
                "contains": "hoge",
                "append": "fuga"
            },
        ]
    },
];

(function(){
    if (!String.prototype.format) {
        String.prototype.format = function () {
            var args = arguments;
            return this.replace(/{(\d+)}/g, function (match, number) {
                return typeof args[number] != 'undefined'? args[number]: match;
            });
        };
    }
})();

var enable = true;

function main(domr) {
    if (!enable)
        return;
    json.forEach((rules) => {
        if (!window.location.pathname.match(new RegExp(rules.path)))
            return;

        rules.rules.forEach((obj) => {
            var props = obj.properties;
            var translate = obj.translate;
            var format = obj.format;
            var contains = obj.contains;
            var append = obj.append;
            var ignoreCase = obj.ignoreCase ? true: false;
            var override = obj.override;
            var add = obj.addClasses;
            var equals = obj.equals == undefined || obj.equals == null ? rules.equals: obj.equals;
            var doms;
            if (!override && rules.selector != undefined && rules.selector != null)
                doms = [document.querySelectorAll(rules.selector)];
            else if (!override && rules.selectors != undefined && rules.selectors != null)
                doms = rules.selectors.map(s => document.querySelectorAll(s));
            else
                doms = obj.selectors.map(s => document.querySelectorAll(s));

            for (var i = 0; i < doms.length; i++)
            {
                var domc = doms[i]
                domc.forEach((dom) => {
                    if (domr != undefined && domr != null && dom != null && !dom == domr)
                        return;
                    props.forEach((prop) => {
                        tr(dom, translate, prop, obj["replace"], format, contains, append, ignoreCase, add, equals);
                    });
                    if (props.length == 0 && format != undefined)
                        tr(dom, translate, null, obj["replace"], format, contains, append, ignoreCase, add, equals);
                    else if (props.length == 0 && obj["replace"] == undefined)
                         tr(dom, translate, null, null, format, contains, append, ignoreCase, add)
                    else if (obj["replace"] != undefined)
                        tr(dom, translate, null, obj["replace"], format, contains, append, ignoreCase, add, equals);
                });

            }
        });

    });
}

var config = {
    childList: true,
    subtree: true,
    attributeOldValue: false,
    attributes: false,
    characterData: false
};

var observer = new MutationObserver((r) => {
    /*var flag = false;
    r.forEach((b) => {
        if (b.target)
            if (b.target.className)
                if (b.target.className.includes("Code"))
                flag = true;
        if (b.nextSibling)
            if (b.nextSibling.className)
                if (b.nextSibling.className.includes("Code"))
                flag = true;
        if (b.previousSibling)
            if (b.previousSibling.className)
                if (b.previousSibling.className.includes("Code"))
                flag = true;
    });
    if (flag)
        return;*/
    observer.disconnect();
    main(null);
    observer.observe(document, config);
});
    observer.observe(document, config);

document.kill = () => {
    enable = false;
}

document.equ = (str, b) => {
    return equ(str,b);
};


document.update = () => {
    main(null)
}
function cca (str, array, ignoreCase) {
    var a = false;
    array.forEach((ab) => {
        if (a)
            return;
        if (ignoreCase)
            a = str.toLowerCase().includes(ab.toLowerCase());
        else a = str.includes(ab);
    });
    return a;
}

function equ (str, equ) {
    var a = false;
    if (equ == undefined || equ == null)
        return true;
    return str.toUpperCase() === equ.toUpperCase();
}

function lower(str, ignoreCase)
{
    return ignoreCase ? str.ignoreCase(): str;
}

function tr(dom, translate, prop, replace, format, contains, append, ignoreCase, add, equals) {
    if (dom == undefined || dom == null)
        return;

    if (contains == null || (contains && !prop && cca(dom.innerHTML, contains, ignoreCase)) || (contains && prop && dom[prop] && cca(dom[prop], contains, ignoreCase) && equ(dom[prop], equals)))
        if (add && add.length != 0)
            add.forEach(s => dom.classList.add(s))

    if (translate != undefined)
    {
        if (prop != null)
        {
            if (contains != undefined && contains != null && dom[prop] != null && dom[prop] != undefined && !cca(dom[prop], contains, ignoreCase) && !equ(dom[prop], equals))
                return;
            if (replace != null && dom[prop] != undefined)
            {
                var a = dom[prop].replace(replace, translate) + (append != undefined && append != null ? append: "");
                if (a != dom[prop])
                    dom[prop] = a;
            }
            else
            {
                var ate = translate + (append != undefined && append != null ? append: "");
                if (ate != dom[prop])
                    dom[prop] = ate;
            }
        }
        else
        {
            if (contains != undefined && contains != null && !cca(dom.innerHTML, contains, ignoreCase) || !equ(dom.innerHTML, equals))
                return;

            if (replace != null)
            {
                var kawr = dom.innerHTML.replace(replace, translate) + (append != undefined && append != null ? append: "");
                if (dom.innerHTML != kawr)
                    dom.innerHTML = kawr
            }
            else
            {
                var sar = translate + (append != undefined && append != null ? append: "");
                if ( dom.innerHTML != sar)
                    dom.innerHTML = sar;
            }
        }

        return;
    }

    if (dom == null)
        return;

    if (format == undefined || format == null)
        return;

    if (prop != null)
    {
        if (document.querySelector(replace) != null)
            if (contains != undefined && contains != null && dom[prop] != null && dom[prop] != undefined && cca(dom[prop], contains, ignoreCase) && equ(dom[prop], equals))
            {
                var propaw = format.format(document.querySelector(replace).outerHTML) + (append != undefined && append != null ? append: "");
                if (dom[prop] != propaw)
                    dom[prop] = propaw;
            }
    }
    else
        if (document.querySelector(replace) != null)
              if (contains != undefined && contains != null && cca(dom.innerHTML, contains, ignoreCase) && equ(dom.innerHTML, equals))
              {
                  var inn =  format.format(document.querySelector(replace).outerHTML) + (append != undefined && append != null ? append: "");
                  if (inn != dom.outerHTML)
                      dom.outerHTML = inn;
              }
}