Userscript to enable Vim mode in most ServiceNow script fields. Also dynamically resizes the editor to fit content

sn-vimify.user.js

// ==UserScript==
// @name        SNOW CodeMirror Vim activator & embiggener
// @description Enables vim mode for ServiceNow in most script editor fields. Also englarges the field!
// @namespace   https://gist.githubusercontent.com/chaorace/dc49a18f876a9814c8b27d637bfb4f44/raw/sn-vimify.user.js
// @updateURL   https://gist.githubusercontent.com/chaorace/dc49a18f876a9814c8b27d637bfb4f44/raw/sn-vimify.user.js
// @supportURL  https://gist.github.com/chaorace/dc49a18f876a9814c8b27d637bfb4f44
// @include     http://*.service-now.com/*
// @include     https://*.service-now.com/*
// @require     https://codemirror.net/keymap/vim.js
// @run-at      document-idle
// ==/UserScript==
(function() {
    // NOTE: This userscript will throw harmless errors if a given frame doesn't have a CodeMirror editor
    // This is something that happens during the loading phase for @require, so we can't suppress it
    if (typeof g_glideEditorArray !== 'undefined' && Array.isArray(g_glideEditorArray)){
        // Apply the below modifications to each major CodeMirror editor
        g_glideEditorArray.forEach((cm) => {
            // Drop the escape keybind that advances to the next field (obviously, we need escape for vim mode!)
            cm.editor.state.keyMaps = cm.editor.state.keyMaps.filter((x) => !x.Esc)
            // Actually set the keymap to the one previously loaded from our @require
            cm.editor.options.keyMap = 'vim'
            // An infinite viewport margin lets the editor grow with content
            cm.editor.options.viewportMargin = Infinity
            // Set the max height to 2/3rds of a screen height
            cm.editor.getScrollerElement().style.maxHeight = '66vh'
        })
    }
})()