Convert frontend code to typescript (#31559)

None of the frontend js/ts files was touched besides these two commands
(edit: no longer true, I touched one file in
61105d0618
because of a deprecation that was not showing before the rename).

`tsc` currently reports 778 errors, so I have disabled it in CI as
planned.

Everything appears to work fine.

web_src/js/utils/dom.ts

@@ -0,0 +1,319 @@
+import {debounce} from 'throttle-debounce';
+
+function elementsCall(el, func, ...args) {
+  if (typeof el === 'string' || el instanceof String) {
+    el = document.querySelectorAll(el);
+  }
+  if (el instanceof Node) {
+    func(el, ...args);
+  } else if (el.length !== undefined) {
+    // this works for: NodeList, HTMLCollection, Array, jQuery
+    for (const e of el) {
+      func(e, ...args);
+    }
+  } else {
+    throw new Error('invalid argument to be shown/hidden');
+  }
+}
+
+/**
+ * @param el string (selector), Node, NodeList, HTMLCollection, Array or jQuery
+ * @param force force=true to show or force=false to hide, undefined to toggle
+ */
+function toggleShown(el, force) {
+  if (force === true) {
+    el.classList.remove('tw-hidden');
+  } else if (force === false) {
+    el.classList.add('tw-hidden');
+  } else if (force === undefined) {
+    el.classList.toggle('tw-hidden');
+  } else {
+    throw new Error('invalid force argument');
+  }
+}
+
+export function showElem(el) {
+  elementsCall(el, toggleShown, true);
+}
+
+export function hideElem(el) {
+  elementsCall(el, toggleShown, false);
+}
+
+export function toggleElem(el, force) {
+  elementsCall(el, toggleShown, force);
+}
+
+export function isElemHidden(el) {
+  const res = [];
+  elementsCall(el, (e) => res.push(e.classList.contains('tw-hidden')));
+  if (res.length > 1) throw new Error(`isElemHidden doesn't work for multiple elements`);
+  return res[0];
+}
+
+function applyElemsCallback(elems, fn) {
+  if (fn) {
+    for (const el of elems) {
+      fn(el);
+    }
+  }
+  return elems;
+}
+
+export function queryElemSiblings(el, selector = '*', fn) {
+  return applyElemsCallback(Array.from(el.parentNode.children).filter((child) => child !== el && child.matches(selector)), fn);
+}
+
+// it works like jQuery.children: only the direct children are selected
+export function queryElemChildren(parent, selector = '*', fn) {
+  return applyElemsCallback(parent.querySelectorAll(`:scope > ${selector}`), fn);
+}
+
+export function queryElems(selector, fn) {
+  return applyElemsCallback(document.querySelectorAll(selector), fn);
+}
+
+export function onDomReady(cb) {
+  if (document.readyState === 'loading') {
+    document.addEventListener('DOMContentLoaded', cb);
+  } else {
+    cb();
+  }
+}
+
+// checks whether an element is owned by the current document, and whether it is a document fragment or element node
+// if it is, it means it is a "normal" element managed by us, which can be modified safely.
+export function isDocumentFragmentOrElementNode(el) {
+  try {
+    return el.ownerDocument === document && el.nodeType === Node.ELEMENT_NODE || el.nodeType === Node.DOCUMENT_FRAGMENT_NODE;
+  } catch {
+    // in case the el is not in the same origin, then the access to nodeType would fail
+    return false;
+  }
+}
+
+// autosize a textarea to fit content. Based on
+// https://github.com/github/textarea-autosize
+// ---------------------------------------------------------------------
+// Copyright (c) 2018 GitHub, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// ---------------------------------------------------------------------
+export function autosize(textarea, {viewportMarginBottom = 0} = {}) {
+  let isUserResized = false;
+  // lastStyleHeight and initialStyleHeight are CSS values like '100px'
+  let lastMouseX, lastMouseY, lastStyleHeight, initialStyleHeight;
+
+  function onUserResize(event) {
+    if (isUserResized) return;
+    if (lastMouseX !== event.clientX || lastMouseY !== event.clientY) {
+      const newStyleHeight = textarea.style.height;
+      if (lastStyleHeight && lastStyleHeight !== newStyleHeight) {
+        isUserResized = true;
+      }
+      lastStyleHeight = newStyleHeight;
+    }
+
+    lastMouseX = event.clientX;
+    lastMouseY = event.clientY;
+  }
+
+  function overflowOffset() {
+    let offsetTop = 0;
+    let el = textarea;
+
+    while (el !== document.body && el !== null) {
+      offsetTop += el.offsetTop || 0;
+      el = el.offsetParent;
+    }
+
+    const top = offsetTop - document.defaultView.scrollY;
+    const bottom = document.documentElement.clientHeight - (top + textarea.offsetHeight);
+    return {top, bottom};
+  }
+
+  function resizeToFit() {
+    if (isUserResized) return;
+    if (textarea.offsetWidth <= 0 && textarea.offsetHeight <= 0) return;
+
+    try {
+      const {top, bottom} = overflowOffset();
+      const isOutOfViewport = top < 0 || bottom < 0;
+
+      const computedStyle = getComputedStyle(textarea);
+      const topBorderWidth = parseFloat(computedStyle.borderTopWidth);
+      const bottomBorderWidth = parseFloat(computedStyle.borderBottomWidth);
+      const isBorderBox = computedStyle.boxSizing === 'border-box';
+      const borderAddOn = isBorderBox ? topBorderWidth + bottomBorderWidth : 0;
+
+      const adjustedViewportMarginBottom = bottom < viewportMarginBottom ? bottom : viewportMarginBottom;
+      const curHeight = parseFloat(computedStyle.height);
+      const maxHeight = curHeight + bottom - adjustedViewportMarginBottom;
+
+      textarea.style.height = 'auto';
+      let newHeight = textarea.scrollHeight + borderAddOn;
+
+      if (isOutOfViewport) {
+        // it is already out of the viewport:
+        // * if the textarea is expanding: do not resize it
+        if (newHeight > curHeight) {
+          newHeight = curHeight;
+        }
+        // * if the textarea is shrinking, shrink line by line (just use the
+        //   scrollHeight). do not apply max-height limit, otherwise the page
+        //   flickers and the textarea jumps
+      } else {
+        // * if it is in the viewport, apply the max-height limit
+        newHeight = Math.min(maxHeight, newHeight);
+      }
+
+      textarea.style.height = `${newHeight}px`;
+      lastStyleHeight = textarea.style.height;
+    } finally {
+      // ensure that the textarea is fully scrolled to the end, when the cursor
+      // is at the end during an input event
+      if (textarea.selectionStart === textarea.selectionEnd &&
+          textarea.selectionStart === textarea.value.length) {
+        textarea.scrollTop = textarea.scrollHeight;
+      }
+    }
+  }
+
+  function onFormReset() {
+    isUserResized = false;
+    if (initialStyleHeight !== undefined) {
+      textarea.style.height = initialStyleHeight;
+    } else {
+      textarea.style.removeProperty('height');
+    }
+  }
+
+  textarea.addEventListener('mousemove', onUserResize);
+  textarea.addEventListener('input', resizeToFit);
+  textarea.form?.addEventListener('reset', onFormReset);
+  initialStyleHeight = textarea.style.height ?? undefined;
+  if (textarea.value) resizeToFit();
+
+  return {
+    resizeToFit,
+    destroy() {
+      textarea.removeEventListener('mousemove', onUserResize);
+      textarea.removeEventListener('input', resizeToFit);
+      textarea.form?.removeEventListener('reset', onFormReset);
+    },
+  };
+}
+
+export function onInputDebounce(fn) {
+  return debounce(300, fn);
+}
+
+// Set the `src` attribute on an element and returns a promise that resolves once the element
+// has loaded or errored. Suitable for all elements mention in:
+// https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/load_event
+export function loadElem(el, src) {
+  return new Promise((resolve) => {
+    el.addEventListener('load', () => resolve(true), {once: true});
+    el.addEventListener('error', () => resolve(false), {once: true});
+    el.src = src;
+  });
+}
+
+// some browsers like PaleMoon don't have "SubmitEvent" support, so polyfill it by a tricky method: use the last clicked button as submitter
+// it can't use other transparent polyfill patches because PaleMoon also doesn't support "addEventListener(capture)"
+const needSubmitEventPolyfill = typeof SubmitEvent === 'undefined';
+
+export function submitEventSubmitter(e) {
+  e = e.originalEvent ?? e; // if the event is wrapped by jQuery, use "originalEvent", otherwise, use the event itself
+  return needSubmitEventPolyfill ? (e.target._submitter || null) : e.submitter;
+}
+
+function submitEventPolyfillListener(e) {
+  const form = e.target.closest('form');
+  if (!form) return;
+  form._submitter = e.target.closest('button:not([type]), button[type="submit"], input[type="submit"]');
+}
+
+export function initSubmitEventPolyfill() {
+  if (!needSubmitEventPolyfill) return;
+  console.warn(`This browser doesn't have "SubmitEvent" support, use a tricky method to polyfill`);
+  document.body.addEventListener('click', submitEventPolyfillListener);
+  document.body.addEventListener('focus', submitEventPolyfillListener);
+}
+
+/**
+ * Check if an element is visible, equivalent to jQuery's `:visible` pseudo.
+ * Note: This function doesn't account for all possible visibility scenarios.
+ * @param {HTMLElement} element The element to check.
+ * @returns {boolean} True if the element is visible.
+ */
+export function isElemVisible(element) {
+  if (!element) return false;
+
+  return Boolean(element.offsetWidth || element.offsetHeight || element.getClientRects().length);
+}
+
+// replace selected text in a textarea while preserving editor history, e.g. CTRL-Z works after this
+export function replaceTextareaSelection(textarea, text) {
+  const before = textarea.value.slice(0, textarea.selectionStart ?? undefined);
+  const after = textarea.value.slice(textarea.selectionEnd ?? undefined);
+  let success = true;
+
+  textarea.contentEditable = 'true';
+  try {
+    success = document.execCommand('insertText', false, text); // eslint-disable-line deprecation/deprecation
+  } catch {
+    success = false;
+  }
+  textarea.contentEditable = 'false';
+
+  if (success && !textarea.value.slice(0, textarea.selectionStart ?? undefined).endsWith(text)) {
+    success = false;
+  }
+
+  if (!success) {
+    textarea.value = `${before}${text}${after}`;
+    textarea.dispatchEvent(new CustomEvent('change', {bubbles: true, cancelable: true}));
+  }
+}
+
+// Warning: Do not enter any unsanitized variables here
+export function createElementFromHTML(htmlString) {
+  const div = document.createElement('div');
+  div.innerHTML = htmlString.trim();
+  return div.firstChild;
+}
+
+export function createElementFromAttrs(tagName, attrs) {
+  const el = document.createElement(tagName);
+  for (const [key, value] of Object.entries(attrs)) {
+    if (value === undefined || value === null) continue;
+    if (value === true) {
+      el.toggleAttribute(key, value);
+    } else {
+      el.setAttribute(key, String(value));
+    }
+    // TODO: in the future we could make it also support "textContent" and "innerHTML" properties if needed
+  }
+  return el;
+}
+
+export function animateOnce(el, animationClassName) {
+  return new Promise((resolve) => {
+    el.addEventListener('animationend', function onAnimationEnd() {
+      el.classList.remove(animationClassName);
+      el.removeEventListener('animationend', onAnimationEnd);
+      resolve();
+    }, {once: true});
+    el.classList.add(animationClassName);
+  });
+}