Support overrideKeystroke on static math

src/commands/math.ts

@@ -708,12 +708,14 @@ API.StaticMath = function (APIClasses: APIClasses) {
 
     __mathquillify(opts: ConfigOptions, _interfaceVersion: number) {
       this.config(opts as MathQuill.v3.Config);
+      // `mathquillify` calls `createTextarea`
       super.mathquillify('mq-math-mode');
       this.__controller.setupStaticField();
       if (this.__options.mouseEvents) {
         this.__controller.addMouseEventListener();
-        this.__controller.staticMathTextareaEvents();
       }
+      // The textarea is initialized (`createTextarea` called) by this point.
+      this.__controller.staticMathTextareaEvents();
       return this;
     }
     constructor(el: Controller) {

src/controller.ts

@@ -157,15 +157,15 @@ class ControllerBase {
     );
   }
 
-  getTextareaOrThrow() {
-    var textarea = this.textarea;
-    if (!textarea) throw new Error('expected a textarea');
+  getTextarea() {
+    const textarea = this.textarea;
+    pray('textarea initialized', textarea);
     return textarea;
   }
 
-  getTextareaSpanOrThrow() {
-    var textareaSpan = this.textareaSpan;
-    if (!textareaSpan) throw new Error('expected a textareaSpan');
+  getTextareaSpan() {
+    const textareaSpan = this.textareaSpan;
+    pray('textareaSpan initialized', textareaSpan);
     return textareaSpan;
   }
 

src/publicapi.ts

@@ -352,12 +352,12 @@ function getInterface(v: number): MathQuill.v3.API | MathQuill.v1.API {
       return this;
     }
     focus() {
-      this.__controller.getTextareaOrThrow().focus();
+      this.__controller.getTextarea().focus();
       if (this.__controller.editable) this.__controller.scrollHoriz();
       return this;
     }
     blur() {
-      this.__controller.getTextareaOrThrow().blur();
+      this.__controller.getTextarea().blur();
       return this;
     }
   }

src/services/mouse.ts

@@ -47,7 +47,7 @@ class Controller_mouse extends Controller_latex {
     var ctrlr = root.controller,
       cursor = ctrlr.cursor,
       blink = cursor.blink;
-    var textarea = ctrlr.getTextareaOrThrow();
+    var textarea = ctrlr.getTextarea();
 
     e.preventDefault(); // doesn't work in IE≤8, but it's a one-line fix:
     (e.target as any).unselectable = true; // http://jsbin.com/yagekiji/1 // TODO - no idea what this unselectable property is

src/services/saneKeyboardEvents.util.ts

@@ -360,6 +360,18 @@ var saneKeyboardEvents = (function () {
       everyTick.trigger(e);
     }
 
+    if (controller.KIND_OF_MQ === 'StaticMath') {
+      controller.addTextareaEventListeners({
+        keydown: (evt) => {
+          // The name `overrideKeystroke` matches the API for editable math,
+          // but it is overriding nothing. It replaces nothing with something.
+          controller.options.overrideKeystroke?.(getMQKeyName(evt!), evt);
+        }
+      });
+
+      return { select };
+    }
+
     if (controller.options && controller.options.disableCopyPaste) {
       controller.addTextareaEventListeners({
         keydown: onKeydown,

src/services/textarea.ts

@@ -71,6 +71,7 @@ class Controller extends Controller_scrollHoriz {
     this.selectFn(latex);
   }
 
+  /** Requires `this.textarea` to be initialized. */
   staticMathTextareaEvents() {
     var ctrlr = this;
     this.removeTextareaEventListener('cut');
@@ -87,18 +88,16 @@ class Controller extends Controller_scrollHoriz {
 
     this.addStaticFocusBlurListeners();
 
-    ctrlr.selectFn = function (text: string) {
-      const textarea = ctrlr.getTextareaOrThrow();
-      if (!(textarea instanceof HTMLTextAreaElement)) return;
-      textarea.value = text;
-      if (text) textarea.select();
-    };
+    const textarea = this.getTextarea();
+    const { select } = saneKeyboardEvents(textarea, this);
+    this.selectFn = select;
   }
 
+  /** Requires `this.textarea` to be initialized. */
   editablesTextareaEvents() {
     var ctrlr = this;
-    const textarea = ctrlr.getTextareaOrThrow();
-    const textareaSpan = ctrlr.getTextareaSpanOrThrow();
+    const textarea = ctrlr.getTextarea();
+    const textareaSpan = ctrlr.getTextareaSpan();
 
     if (this.options.version < 3) {
       const $ = this.options.assertJquery();
@@ -118,10 +117,11 @@ class Controller extends Controller_scrollHoriz {
     this.addEditableFocusBlurListeners();
     this.updateMathspeak();
   }
+
   unbindEditablesEvents() {
     var ctrlr = this;
-    const textarea = ctrlr.getTextareaOrThrow();
-    const textareaSpan = ctrlr.getTextareaSpanOrThrow();
+    const textarea = ctrlr.getTextarea();
+    const textareaSpan = ctrlr.getTextareaSpan();
 
     this.selectFn = function (text: string) {
       if (!(textarea instanceof HTMLTextAreaElement)) return;
@@ -203,7 +203,7 @@ class Controller extends Controller_scrollHoriz {
     var mathspeak = ctrlr.root.mathspeak().trim();
     this.aria.clear();
 
-    const textarea = ctrlr.getTextareaOrThrow();
+    const textarea = ctrlr.getTextarea();
     // For static math, provide mathspeak in a visually hidden span to allow screen readers and other AT to traverse the content.
     // For editable math, assign the mathspeak to the textarea's ARIA label (AT can use text navigation to interrogate the content).
     // Be certain to include the mathspeak for only one of these, though, as we don't want to include outdated labels if a field's editable state changes.

test/unit/publicapi.test.js

@@ -1077,6 +1077,17 @@ suite('Public API', function () {
       trigger.keydown(mq.el().querySelector('textarea'), 'ArrowLeft');
       assert.equal(key, 'Left');
     });
+    test('can intercept key events on static', function () {
+      var mq = MQ.StaticMath($('<span>').appendTo('#mock')[0], {
+        overrideKeystroke: function (_key, evt) {
+          key = _key;
+        }
+      });
+      var key;
+
+      trigger.keydown(mq.el().querySelector('textarea'), 'ArrowLeft');
+      assert.equal(key, 'Left');
+    });
     test('cut is async', function (done) {
       var mq = MQ.MathField($('<span>').appendTo('#mock')[0], {
         onCut: function () {