switch bull-codemirror to typescript

The TypeScript compiler (tsc) passes, but is not wired up,
so you need to install it yourself:

    % npm install -g typescript
    % tsc

Author: stapelberg

internal/codemirror/bull-codemirror.bundle.js

@@ -9,7 +9,7 @@ import {markdown} from "@codemirror/lang-markdown"
 import {keymap, highlightSpecialChars, drawSelection, highlightActiveLine, dropCursor,
         rectangularSelection, crosshairCursor,
         lineNumbers, highlightActiveLineGutter} from "@codemirror/view"
-import {Extension, EditorState} from "@codemirror/state"
+import {EditorState} from "@codemirror/state"
 import {defaultHighlightStyle, syntaxHighlighting, indentOnInput, bracketMatching,
         foldGutter, foldKeymap} from "@codemirror/language"
 import {defaultKeymap, history, historyKeymap, indentWithTab} from "@codemirror/commands"
@@ -53,6 +53,8 @@ let bullSetup = [
     ]),
 ]
 
+declare var BullMarkdown: string
+
 let editor = new EditorView({
     doc: BullMarkdown,
     extensions: [
@@ -66,6 +68,7 @@ let editor = new EditorView({
 editor.focus();
 
 // Inject the editor content into the <form> before submit
-document.getElementById('bull-save').onclick = function(event) {
-    document.getElementById('bull-markdown').value = editor.state.doc.toString();
+document.getElementById('bull-save').onclick = function(_unused) {
+    var bullMarkdown = <HTMLTextAreaElement>document.getElementById('bull-markdown');
+    bullMarkdown.value = editor.state.doc.toString();
 }

internal/codemirror/bull-codemirror.jsx internal/codemirror/bull-codemirror.ts

@@ -2,7 +2,7 @@
 
 export NODE_PATH=$PWD/third_party/codemirror/node_modules
 go tool esbuild \
-   internal/codemirror/bull-codemirror.jsx \
+   internal/codemirror/bull-codemirror.ts \
    --bundle \
    --minify \
    --outfile=internal/codemirror/bull-codemirror.bundle.js

regenerate.sh

@@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "target": "es2019",
+    "module": "commonjs",
+    "alwaysStrict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noImplicitReturns": true,
+    "moduleResolution": "node",
+    "baseUrl": "./third_party/codemirror/node_modules",
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true
+  },
+  "include": [
+    "internal/codemirror/*.ts"
+  ],
+  "exclude": [
+    "third_party/codemirror/node_modules"
+  ]
+}