dsck.user.js

// ==UserScript==
// @name         Dog Square Custom Keymap
// @version      0.1
// @description  Custom keymap
// @author       Saren
// @match        https://tobychui.github.io/Dog-Square/
// @grant        none
// @run-at       document-start
// ==/UserScript==

// ,./kl;iop890
let map = {
    '188': 96,
    '190': 96,
    '191': 110,
    '75': 97,
    '76': 98,
    '186': 99,
    '73': 100,
    '79': 101,
    '80': 102,
    '56': 103,
    '57': 104,
    '48': 105,
};

let orig = EventTarget.prototype.addEventListener;
EventTarget.prototype.addEventListener = function (...args) {
    if (args[0] !== 'keydown') {
        orig(...args);
        return;
    }
    let oFn = args[1];
    args[1] = function (e) {
        let newCode = map[e.which.toString()];
        console.log('Pressed', e);
        if (newCode) {
            Object.defineProperty(e, 'which', {
                value: newCode,
                writable: false
            });
        }
        oFn(e);
    };
    orig(...args);
};