improve typing

.eslintrc.js

@@ -133,7 +133,7 @@ module.exports = {
     'dot-notation': [ERROR, {allowPattern: '^(error|warn)$'}],
 
     'eol-last': ERROR,
-    eqeqeq: [ERROR, 'allow-null'],
+    eqeqeq: [ERROR, 'always'],
     // Prettier forces semicolons in a few places
     'flowtype/object-type-delimiter': OFF,
 

packages/lexical-clipboard/src/clipboard.ts

@@ -49,7 +49,7 @@ const getDOMSelection = (targetWindow: Window | null): Selection | null =>
 export function $getHtmlContent(editor: LexicalEditor): string {
   const selection = $getSelection();
 
-  if (selection == null) {
+  if (selection === null) {
     invariant(false, 'Expected valid LexicalSelection');
   }
 
@@ -76,7 +76,7 @@ export function $getHtmlContent(editor: LexicalEditor): string {
 export function $getLexicalContent(editor: LexicalEditor): null | string {
   const selection = $getSelection();
 
-  if (selection == null) {
+  if (selection === null) {
     invariant(false, 'Expected valid LexicalSelection');
   }
 
@@ -106,9 +106,7 @@ export function $insertDataTransferForPlainText(
   const text =
     dataTransfer.getData('text/plain') || dataTransfer.getData('text/uri-list');
 
-  if (text != null) {
-    selection.insertRawText(text);
-  }
+  selection.insertRawText(text);
 }
 
 /**
@@ -159,7 +157,7 @@ export function $insertDataTransferForRichText(
   // Webkit-specific: Supports read 'text/uri-list' in clipboard.
   const text =
     dataTransfer.getData('text/plain') || dataTransfer.getData('text/uri-list');
-  if (text != null) {
+  if (text !== '') {
     if ($isRangeSelection(selection)) {
       const parts = text.split(/(\r?\n|\t)/);
       if (parts[parts.length - 1] === '') {
@@ -399,7 +397,7 @@ export async function copyToClipboard(
 
   const rootElement = editor.getRootElement();
   const windowDocument =
-    editor._window == null ? window.document : editor._window.document;
+    editor._window === null ? window.document : editor._window.document;
   const domSelection = getDOMSelection(editor._window);
   if (rootElement === null || domSelection === null) {
     return false;

packages/lexical-code/src/CodeHighlighter.ts

@@ -695,7 +695,7 @@ function handleShiftLines(
     start = getFirstCodeNodeOfLine(focusNode);
     end = getLastCodeNodeOfLine(anchorNode);
   }
-  if (start == null || end == null) {
+  if (start === null || end === null) {
     return false;
   }
 
@@ -726,7 +726,7 @@ function handleShiftLines(
   const sibling = arrowIsUp
     ? linebreak.getPreviousSibling()
     : linebreak.getNextSibling();
-  if (sibling == null) {
+  if (sibling === null) {
     return true;
   }
 
@@ -739,7 +739,7 @@ function handleShiftLines(
         : getLastCodeNodeOfLine(sibling)
       : null;
   let insertionPoint =
-    maybeInsertionPoint != null ? maybeInsertionPoint : sibling;
+    maybeInsertionPoint !== null ? maybeInsertionPoint : sibling;
   linebreak.remove();
   range.forEach((node) => node.remove());
   if (type === KEY_ARROW_UP_COMMAND) {
@@ -813,7 +813,7 @@ export function registerCodeHighlighting(
     );
   }
 
-  if (tokenizer == null) {
+  if (tokenizer === undefined) {
     tokenizer = PrismTokenizer;
   }
 

packages/lexical-code/src/CodeNode.ts

@@ -51,8 +51,9 @@ export type SerializedCodeNode = Spread<
 const mapToPrismLanguage = (
   language: string | null | undefined,
 ): string | null | undefined => {
-  // eslint-disable-next-line no-prototype-builtins
-  return language != null && window.Prism.languages.hasOwnProperty(language)
+  return language !== null &&
+    language !== undefined &&
+    Object.hasOwn(window.Prism.languages, language)
     ? language
     : undefined;
 };
@@ -134,7 +135,7 @@ export class CodeNode extends ElementNode {
       // inline format handled by TextNode otherwise.
       code: (node: Node) => {
         const isMultiLine =
-          node.textContent != null &&
+          node.textContent !== null &&
           (/\r?\n/.test(node.textContent) || hasChildDOMNodeTag(node, 'BR'));
 
         return isMultiLine
@@ -350,7 +351,7 @@ function convertDivElement(domNode: Node): DOMConversionOutput {
   return {
     after: (childLexicalNodes) => {
       const domParent = domNode.parentNode;
-      if (domParent != null && domNode !== domParent.lastChild) {
+      if (domParent !== null && domNode !== domParent.lastChild) {
         childLexicalNodes.push($createLineBreakNode());
       }
       return childLexicalNodes;

packages/lexical-devtools-core/src/generateContent.ts

@@ -340,7 +340,7 @@ function printFormatProperties(nodeOrSelection: TextNode | RangeSelection) {
 function printTargetProperties(node: LinkNode) {
   let str = node.getTarget();
   // TODO Fix nullish on LinkNode
-  if (str != null) {
+  if (str !== null) {
     str = 'target: ' + str;
   }
   return str;
@@ -349,7 +349,7 @@ function printTargetProperties(node: LinkNode) {
 function printRelProperties(node: LinkNode) {
   let str = node.getRel();
   // TODO Fix nullish on LinkNode
-  if (str != null) {
+  if (str !== null) {
     str = 'rel: ' + str;
   }
   return str;
@@ -358,7 +358,7 @@ function printRelProperties(node: LinkNode) {
 function printTitleProperties(node: LinkNode) {
   let str = node.getTitle();
   // TODO Fix nullish on LinkNode
-  if (str != null) {
+  if (str !== null) {
     str = 'title: ' + str;
   }
   return str;

packages/lexical-devtools/src/entrypoints/injected/InjectedPegasusService.ts

@@ -44,7 +44,7 @@ export class InjectedPegasusService
     isReadonly: boolean,
   ): void {
     const editorNode = queryLexicalNodeByKey(editorKey);
-    if (editorNode == null) {
+    if (editorNode === undefined) {
       throw new Error(`Can't find editor with key: ${editorKey}`);
     }
 
@@ -57,7 +57,7 @@ export class InjectedPegasusService
     exportDOM: boolean,
   ): string {
     const editor = queryLexicalEditorByKey(editorKey);
-    if (editor == null) {
+    if (editor === undefined) {
       throw new Error(`Can't find editor with key: ${editorKey}`);
     }
 
@@ -72,7 +72,7 @@ export class InjectedPegasusService
     editorState: SerializedRawEditorState,
   ): void {
     const editor = queryLexicalEditorByKey(editorKey);
-    if (editor == null) {
+    if (editor === undefined) {
       throw new Error(`Can't find editor with key: ${editorKey}`);
     }
 

packages/lexical-devtools/src/serializeEditorState.ts

@@ -37,7 +37,7 @@ export function deserializeEditorState(
     typeof editorState.deserealizationID === 'number'
   ) {
     const state = deserealizationMap.get(editorState.deserealizationID);
-    if (state == null) {
+    if (state === undefined) {
       throw new Error(
         `Can't find deserealization ref for state with id ${editorState.deserealizationID}`,
       );
@@ -64,7 +64,7 @@ export function serializeEditorState(
     selection &&
     'anchor' in selection &&
     typeof selection.anchor === 'object' &&
-    selection.anchor != null
+    selection.anchor !== null
   ) {
     // remove _selection.anchor._selection property if present in RangeSelection or GridSelection
     // otherwise, the recursive structure makes the selection object unserializable
@@ -74,7 +74,7 @@ export function serializeEditorState(
     selection &&
     'focus' in selection &&
     typeof selection.focus === 'object' &&
-    selection.focus != null
+    selection.focus !== null
   ) {
     // remove _selection.anchor._selection property if present in RangeSelection or GridSelection
     // otherwise, the recursive structure makes the selection object unserializable

packages/lexical-html/src/index.ts

@@ -224,7 +224,7 @@ function $createNodesFromDOM(
       }
     }
 
-    if (transformOutput.forChild != null) {
+    if (transformOutput.forChild !== undefined) {
       forChildMap.set(node.nodeName, transformOutput.forChild);
     }
   }
@@ -245,11 +245,11 @@ function $createNodesFromDOM(
     );
   }
 
-  if (postTransform != null) {
+  if (postTransform !== null && postTransform !== undefined) {
     childLexicalNodes = postTransform(childLexicalNodes);
   }
 
-  if (currentLexicalNode == null) {
+  if (currentLexicalNode === null || currentLexicalNode === undefined) {
     // If it hasn't been converted to a LexicalNode, we hoist its children
     // up to the same level as it.
     lexicalNodes = lexicalNodes.concat(childLexicalNodes);

packages/lexical-list/src/LexicalListItemNode.ts

@@ -102,12 +102,15 @@ export class ListItemNode extends ElementNode {
   static transform(): (node: LexicalNode) => void {
     return (node: LexicalNode) => {
       invariant($isListItemNode(node), 'node is not a ListItemNode');
-      if (node.__checked == null) {
+      if (node.__checked === undefined) {
         return;
       }
       const parent = node.getParent();
       if ($isListNode(parent)) {
-        if (parent.getListType() !== 'check' && node.getChecked() != null) {
+        if (
+          parent.getListType() !== 'check' &&
+          node.getChecked() !== undefined
+        ) {
           node.setChecked(undefined);
         }
       }
@@ -261,7 +264,7 @@ export class ListItemNode extends ElementNode {
     restoreSelection = true,
   ): ListItemNode | ParagraphNode {
     const newElement = $createListItemNode(
-      this.__checked == null ? undefined : false,
+      this.__checked === undefined ? undefined : false,
     );
     this.insertAfter(newElement, restoreSelection);
 

packages/lexical-list/src/formatList.ts

@@ -115,7 +115,7 @@ export function insertList(editor: LexicalEditor, listType: ListType): void {
 
         if ($isLeafNode(node)) {
           let parent = node.getParent();
-          while (parent != null) {
+          while (parent !== null) {
             const parentKey = parent.getKey();
 
             if ($isListNode(parent)) {
@@ -242,7 +242,7 @@ export function removeList(editor: LexicalEditor): void {
           if ($isLeafNode(node)) {
             const listItemNode = $getNearestNodeOfType(node, ListItemNode);
 
-            if (listItemNode != null) {
+            if (listItemNode !== null) {
               listNodes.add($getTopListNode(listItemNode));
             }
           }
@@ -297,7 +297,7 @@ export function updateChildrenListItemValue(list: ListNode): void {
       if (child.getValue() !== value) {
         child.setValue(value);
       }
-      if (isNotChecklist && child.getChecked() != null) {
+      if (isNotChecklist && child.getChecked() !== undefined) {
         child.setChecked(undefined);
       }
       if (!$isListNode(child.getFirstChild())) {

packages/lexical-list/src/utils.ts

@@ -28,7 +28,7 @@ export function $getListDepth(listNode: ListNode): number {
   let depth = 1;
   let parent = listNode.getParent();
 
-  while (parent != null) {
+  while (parent !== null) {
     if ($isListItemNode(parent)) {
       const parentList = parent.getParent();
 
@@ -176,13 +176,13 @@ export function $removeHighestEmptyListParent(
   let emptyListPtr = sublist;
 
   while (
-    emptyListPtr.getNextSibling() == null &&
-    emptyListPtr.getPreviousSibling() == null
+    emptyListPtr.getNextSibling() === null &&
+    emptyListPtr.getPreviousSibling() === null
   ) {
     const parent = emptyListPtr.getParent<ListItemNode | ListNode>();
 
     if (
-      parent == null ||
+      parent === null ||
       !($isListItemNode(emptyListPtr) || $isListNode(emptyListPtr))
     ) {
       break;

packages/lexical-mark/src/index.ts

@@ -99,7 +99,7 @@ export function $wrapSelectionInMarkNode(
         continue;
       }
       const parentNode = targetNode.getParent();
-      if (parentNode == null || !parentNode.is(currentNodeParent)) {
+      if (parentNode === null || !parentNode.is(currentNodeParent)) {
         // If the parent node is not the current node's parent node, we can
         // clear the last created mark node.
         lastCreatedMarkNode = undefined;

packages/lexical-markdown/src/MarkdownExport.ts

@@ -47,7 +47,7 @@ export function createMarkdownExport(
         byType.textMatch,
       );
 
-      if (result != null) {
+      if (result !== null) {
         output.push(result);
       }
     }
@@ -67,7 +67,7 @@ function exportTopLevelElements(
       exportChildren(_node, textTransformersIndex, textMatchTransformers),
     );
 
-    if (result != null) {
+    if (result !== null) {
       return result;
     }
   }
@@ -103,7 +103,7 @@ function exportChildren(
           exportTextFormat(textNode, textContent, textTransformersIndex),
       );
 
-      if (result != null) {
+      if (result !== null) {
         output.push(result);
         continue mainLoop;
       }