Userscript that enables the [mcve] shortcut in the StackOverflow chat

SOchat_mcve_shortcut.user.js

// ==UserScript==
// @name         SOchat [mcve] shortcut
// @description  Enables the [mcve] shortcut in StackOverflow chat
// @version      1.1.3
// @author       Paul Pinterits
// @include      *://chat.stackoverflow.com/rooms/*
// @grant        none
// @updateURL    https://gist.github.com/Aran-Fey/e5a3fbd5de70d093e7b490ad46117819/raw/SOchat_mcve_shortcut.user.js
// @downloadURL  https://gist.github.com/Aran-Fey/e5a3fbd5de70d093e7b490ad46117819/raw/SOchat_mcve_shortcut.user.js
// ==/UserScript==


(function(){
    'use strict';
    
    const REPLACEMENTS = {
        mcve: 'Minimal, Complete, and Verifiable Example',
        mvce: 'Minimal, Complete, and Verifiable Example',
        reprex: 'Minimal, Reproducible Example',
        repro: 'Minimal, Reproducible Example',
        ruprecht: 'Minimal, Reproducible Example',  // https://chat.stackoverflow.com/transcript/6?m=46410725#46410725
        mre: 'Minimal, Reproducible Example',
        mwe: 'Minimal, Reproducible Example',
        example: 'Minimal, Reproducible Example'
    };
    
    Object.keys(REPLACEMENTS).forEach(function(shorthand){
        const title = REPLACEMENTS[shorthand];
        
        const link = '[' + title + '](https://stackoverflow.com/help/mcve)';
        
        REPLACEMENTS[shorthand] = link;
    });
    
    function fix_message(textbox){
        var text = textbox.value;
        
        Object.keys(REPLACEMENTS).forEach(function(shorthand){
            const link = REPLACEMENTS[shorthand];
            shorthand = '[' + shorthand + ']';
            
            text = text.replace(shorthand, link);
        });
        
        textbox.value = text;
    }

    function run(){
        const textbox = document.getElementById('input');
        const send_button = document.getElementById('sayit-button');

        function button_maybe_clicked(event){
            if (event.target == send_button)
                fix_message(textbox);
        }

        function on_key_press(event){
            const key = event.keyCode ? event.keyCode : event.which;
            if (key == 13 && !event.shiftKey) // Enter and not Shift
                fix_message(textbox);
        }

        send_button.parentElement.addEventListener('click', button_maybe_clicked, true);
        window.addEventListener('keydown', on_key_press, true);
    }

    run();
})();