Real work on getting CodeMirror working. I at least have a fancy highlighter and basic editor.

src/lib/e_app_codemirror.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-// *** Import Svelte specific
+// *** Import Svelte version 5 specific
 import { browser } from '$app/environment';
 
 // BEGIN: CodeMirror
@@ -19,7 +19,7 @@ import {languages} from "@codemirror/language-data"
 import { css } from "@codemirror/lang-css";
 import { html } from "@codemirror/lang-html";
 import {javascript} from "@codemirror/lang-javascript";
-import {markdown} from "@codemirror/lang-markdown"
+import {markdown} from "@codemirror/lang-markdown";
 import { oneDark } from "@codemirror/theme-one-dark";
 
 // END: CodeMirror

src/lib/e_app_codemirror_sv4.svelte

@@ -0,0 +1,226 @@
+<script lang="ts" context="module">
+    export type ThemeSpec = Record<string, StyleSpec>;
+    export type StyleSpec = {
+        [propOrSelector: string]: string | number | StyleSpec | null;
+    };
+</script>
+
+<script lang="ts">
+    import { createEventDispatcher, onDestroy, onMount } from "svelte";
+    import { basicSetup } from "codemirror";
+    import { EditorView, keymap, placeholder as placeholderExt } from "@codemirror/view";
+    import { EditorState, StateEffect, type Extension } from "@codemirror/state";
+    import { indentWithTab } from "@codemirror/commands";
+    import { indentUnit, type LanguageSupport } from "@codemirror/language";
+    import { debounce } from "./util";
+
+    let classes = "";
+    export { classes as class };
+    export let value: string | null | undefined = "";
+
+    export let basic = true;
+    export let lang: LanguageSupport | null | undefined = undefined;
+    export let theme: Extension | null | undefined = undefined;
+    export let extensions: Extension[] = [];
+
+    export let useTab = true;
+    export let tabSize = 2;
+
+    export let styles: ThemeSpec | null | undefined = undefined;
+    export let lineWrapping = false;
+    export let editable = true;
+    export let readonly = false;
+    export let placeholder: string | HTMLElement | null | undefined = undefined;
+
+    export let nodebounce = false;
+
+    const is_browser = typeof window !== "undefined";
+    const dispatch = createEventDispatcher<{ change: string, ready: EditorView, reconfigure: EditorView }>();
+
+    let element: HTMLDivElement;
+    let view: EditorView;
+
+    let update_from_prop = false;
+    let update_from_state = false;
+    let first_config = true;
+    let first_update = true;
+
+    $: state_extensions = [
+        ...get_base_extensions(basic, useTab, tabSize, lineWrapping, placeholder, editable, readonly, lang),
+        ...get_theme(theme, styles),
+        ...extensions,
+    ];
+
+    $: view && update(value);
+    $: view && state_extensions && reconfigure();
+
+    $: on_change = nodebounce ? handle_change : debounce(handle_change, 300);
+
+    onMount(() => {
+        view = create_editor_view();
+        dispatch('ready', view);
+    });
+    onDestroy(() => view?.destroy());
+
+    function create_editor_view(): EditorView {
+        return new EditorView({
+            parent: element,
+            state: create_editor_state(value),
+            dispatch(transaction) {
+                view.update([transaction]);
+
+                if (!update_from_prop && transaction.docChanged) {
+                    on_change();
+                }
+            },
+        });
+    }
+
+    function reconfigure(): void {
+        if (first_config) {
+            first_config = false;
+            return;
+        }
+
+        view.dispatch({
+            effects: StateEffect.reconfigure.of(state_extensions),
+        });
+
+        dispatch('reconfigure', view);
+    }
+
+    function update(value: string | null | undefined): void {
+        if (first_update) {
+            first_update = false;
+            return;
+        }
+
+        if (update_from_state) {
+            update_from_state = false;
+            return;
+        }
+
+        update_from_prop = true;
+
+        view.setState(create_editor_state(value));
+
+        update_from_prop = false;
+    }
+
+    function handle_change(): void {
+        const new_value = view.state.doc.toString();
+        if (new_value === value) return;
+
+        update_from_state = true;
+
+        value = new_value;
+        dispatch("change", value);
+    }
+
+    function create_editor_state(value: string | null | undefined): EditorState {
+        return EditorState.create({
+            doc: value ?? undefined,
+            extensions: state_extensions,
+        });
+    }
+
+    function get_base_extensions(
+        basic: boolean,
+        useTab: boolean,
+        tabSize: number,
+        lineWrapping: boolean,
+        placeholder: string | HTMLElement | null | undefined,
+        editable: boolean,
+        readonly: boolean,
+        lang: LanguageSupport | null | undefined
+    ): Extension[] {
+        const extensions: Extension[] = [
+            indentUnit.of(" ".repeat(tabSize)),
+            EditorView.editable.of(editable),
+            EditorState.readOnly.of(readonly),
+        ];
+
+        if (basic) extensions.push(basicSetup);
+        if (useTab) extensions.push(keymap.of([indentWithTab]));
+        if (placeholder) extensions.push(placeholderExt(placeholder));
+        if (lang) extensions.push(lang);
+        if (lineWrapping) extensions.push(EditorView.lineWrapping);
+
+        return extensions;
+    }
+
+    function get_theme(theme: Extension | null | undefined, styles: ThemeSpec | null | undefined): Extension[] {
+        const extensions: Extension[] = [];
+        if (styles) extensions.push(EditorView.theme(styles));
+        if (theme) extensions.push(theme);
+        return extensions;
+    }
+</script>
+
+{#if is_browser}
+    <div class="codemirror-wrapper {classes}" bind:this={element} />
+{:else}
+    <div class="scm-waiting {classes}">
+        <div class="scm-waiting__loading scm-loading">
+            <div class="scm-loading__spinner" />
+            <p class="scm-loading__text">Loading editor...</p>
+        </div>
+
+        <pre class="scm-pre cm-editor">{value}</pre>
+    </div>
+{/if}
+
+<style>
+    .codemirror-wrapper :global(.cm-focused) {
+        outline: none;
+    }
+
+    .scm-waiting {
+        position: relative;
+    }
+    .scm-waiting__loading {
+        position: absolute;
+        top: 0;
+        left: 0;
+        bottom: 0;
+        right: 0;
+        background-color: rgba(255, 255, 255, 0.5);
+    }
+
+    .scm-loading {
+        display: flex;
+        align-items: center;
+        justify-content: center;
+    }
+    .scm-loading__spinner {
+        width: 1rem;
+        height: 1rem;
+        border-radius: 100%;
+        border: solid 2px #000;
+        border-top-color: transparent;
+        margin-right: 0.75rem;
+        animation: spin 1s linear infinite;
+    }
+    .scm-loading__text {
+        font-family: sans-serif;
+    }
+    .scm-pre {
+        font-size: 0.85rem;
+        font-family: monospace;
+        tab-size: 2;
+        -moz-tab-size: 2;
+        resize: none;
+        pointer-events: none;
+        user-select: none;
+        overflow: auto;
+    }
+
+    @keyframes spin {
+        0% {
+            transform: rotate(0deg);
+        }
+        100% {
+            transform: rotate(360deg);
+        }
+    }
+</style>

src/lib/e_app_codemirror_v5.svelte

@@ -0,0 +1,76 @@
+<script lang="ts">
+    import { onMount, onDestroy, createEventDispatcher } from 'svelte';
+    import { EditorView, keymap, placeholder as placeholderExt } from '@codemirror/view';
+    import { EditorState, StateEffect, type Extension } from '@codemirror/state';
+    import { indentWithTab } from '@codemirror/commands';
+    import { basicSetup } from 'codemirror';
+    import { javascript } from '@codemirror/lang-javascript';
+    import { oneDark } from "@codemirror/theme-one-dark";
+
+    // Props
+    export let content: string = 'test test test test';
+    export let new_content: string = '';
+    export let language: Extension = javascript();
+    export let theme: Extension = oneDark;
+    export let extensions: Extension[] = [];
+    export let editable: boolean = true;
+    export let placeholder: string = 'Start typing...';
+
+    const dispatch = createEventDispatcher<{ change: string }>();
+
+    let editor_element: HTMLDivElement;
+    let editorView: EditorView;
+
+    // Reactive declaration for extensions
+    $: editor_extensions = [
+        basicSetup,
+        EditorView.editable.of(editable),
+        keymap.of([indentWithTab]),
+        placeholderExt(placeholder),
+        language,
+        theme,
+        ...extensions
+    ];
+
+    // Initialize CodeMirror on mount
+    onMount(() => {
+        editorView = new EditorView({
+            state: EditorState.create({
+                doc: content,
+                extensions: editor_extensions,
+            }),
+            parent: editor_element,
+            dispatch: (transaction) => {
+                editorView.update([transaction]);
+                if (transaction.docChanged) {
+                    new_content = editorView.state.doc.toString();
+                    const newContent = editorView.state.doc.toString();
+                    dispatch('change', newContent);
+                }
+            }
+        });
+    });
+
+    // Clean up on destroy
+    onDestroy(() => {
+        editorView?.destroy();
+    });
+
+    // Update editor content when `content` prop changes
+    $: if (editorView && editorView.state.doc.toString() !== content) {
+        editorView.setState(
+            EditorState.create({
+                doc: content,
+                extensions: editor_extensions
+            })
+        );
+    };
+</script>
+
+<div bind:this={editor_element} class="codemirror-wrapper"></div>
+
+<style>
+    .codemirror-wrapper :global(.cm-focused) {
+        outline: none;
+    }
+</style>

src/routes/journals/ae_comp__journal_entry_obj_id_view.svelte

@@ -25,7 +25,11 @@ import {
     } from '@lucide/svelte';
 
 
-import E_app_codemirror from '$lib/e_app_codemirror.svelte';
+// import E_app_codemirror from '$lib/e_app_codemirror.svelte';
+// import E_app_codemirror_v4 from '$lib/e_app_codemirror_v4.svelte';
+import E_app_codemirror_v5 from '$lib/e_app_codemirror_v5.svelte';
+import {javascript} from "@codemirror/lang-javascript";
+import {markdown} from "@codemirror/lang-markdown";
 
 
 // *** Import Aether specific variables and functions
@@ -2038,18 +2042,30 @@ zzzz
     {@html test_html}
 </div> -->
 
-xxx
+{#if $ae_loc.edit_mode && $ae_loc.trusted_access}
 <div
     id="journal_entry_codemirror"
+    class:hidden={!$ae_loc.edit_mode}
     >
     <!-- {cm_view} -->
     <!-- <CodeMirror bind:value class="editor" {...props} /> -->
     <!-- bind:value={cm_view} -->
-    <E_app_codemirror
+    <!-- <E_app_codemirror
         classes="editor"
+        /> -->
+        <!-- bind:content={tmp_entry_obj.content} -->
+    <E_app_codemirror_v5
+        bind:content={tmp_entry_obj.content}
+        bind:new_content={tmp_entry_obj.new_content}
+        language={markdown()}
+        placeholder="Write your JavaScript code here..."
         />
+
+    <pre>
+    {tmp_entry_obj.new_content}
+    </pre>
 </div>
-zzz
+{/if}
 
 <section class="ae_meta flex flex-row flex-wrap gap-1 items-center justify-between w-full">