test: test under ESLint v10 (#663)

Fixes #655.

**Title:** chore: add ESLint 10 CI testing and remove deprecated `type`
from test errors

## Summary

- Removed the `type` property from RuleTester error objects across 21
test files (168 instances). ESLint 10 throws if `type` is present in
invalid test case errors. This is backward-compatible with ESLint 8/9
since `type` was always optional.
- Added a CI step to run unit tests against ESLint 10 on Node 20.x,
following the same pattern used historically when adding ESLint 8
support.
- Bumped `@typescript-eslint/parser` to 8.54.0 for ESLint 10
compatibility (`ScopeManager#addGlobals`).

## Test plan

- All 1353 tests pass on both ESLint 9 and ESLint 10.

Author: bmish

.github/workflows/ci.yml

@@ -30,6 +30,10 @@ jobs:
     - run: npm ci
     - run: npm run test:unit
 
+    - name: Test with ESLint v10
+      if: matrix.node-version == '20.x'
+      run: npm install --save-dev eslint@10 && npm run test:unit
+
     - name: Coveralls
       uses: coverallsapp/github-action@v2
       with:

lib/rules/no-arrow-tests.js

@@ -168,7 +168,7 @@ module.exports = {
          * @returns {boolean}
          */
         function isPropertyInModule(propertyNode) {
-            return (
+            return !!(
                 propertyNode &&
                 propertyNode.parent &&
                 propertyNode.parent.type === "ObjectExpression" &&

lib/rules/no-assert-equal.js

@@ -164,7 +164,7 @@ module.exports = {
          * @returns {boolean}
          */
         function isModuleHookCallback(propertyNode) {
-            return (
+            return !!(
                 propertyNode.parent &&
                 propertyNode.parent.type === "Property" &&
                 utils.isModuleHookPropertyKey(propertyNode.parent.key) &&
@@ -240,7 +240,8 @@ module.exports = {
                 /* istanbul ignore next: deprecated code paths only followed by old eslint versions */
                 const scope = sourceCode.getScope
                     ? sourceCode.getScope(node)
-                    : context.getScope();
+                    : // @ts-expect-error -- removed in ESLint 10, but needed for ESLint 8 compat
+                      context.getScope();
 
                 const tracker = new ReferenceTracker(scope);
                 const traceMap = { equal: { [ReferenceTracker.CALL]: true } };

lib/rules/no-conditional-assertions.js

@@ -76,6 +76,7 @@ module.exports = {
          * @param {import('eslint').Rule.Node} assertNode
          */
         function checkAndReport(assertNode) {
+            /** @type {import('eslint').Rule.Node | null} */
             let currentNode = assertNode;
 
             while (
@@ -86,7 +87,7 @@ module.exports = {
                 currentNode = currentNode.parent;
             }
 
-            if (CONDITIONAL_NODE_TYPES.has(currentNode.type)) {
+            if (currentNode && CONDITIONAL_NODE_TYPES.has(currentNode.type)) {
                 context.report({
                     node: assertNode,
                     messageId: "noAssertionInsideConditional",

lib/rules/no-global-assertions.js

@@ -40,7 +40,8 @@ module.exports = {
                 /* istanbul ignore next: deprecated code paths only followed by old eslint versions */
                 const scope = sourceCode.getScope
                     ? sourceCode.getScope(node)
-                    : context.getScope();
+                    : // @ts-expect-error -- removed in ESLint 10, but needed for ESLint 8 compat
+                      context.getScope();
 
                 const tracker = new ReferenceTracker(scope);
                 /** @type {Record<string, { [ReferenceTracker.CALL]: boolean }>} */

lib/rules/no-global-expect.js

@@ -38,7 +38,8 @@ module.exports = {
                 /* istanbul ignore next: deprecated code paths only followed by old eslint versions */
                 const scope = sourceCode.getScope
                     ? sourceCode.getScope(node)
-                    : context.getScope();
+                    : // @ts-expect-error -- removed in ESLint 10, but needed for ESLint 8 compat
+                      context.getScope();
 
                 const tracker = new ReferenceTracker(scope);
                 const traceMap = { expect: { [ReferenceTracker.CALL]: true } };

lib/rules/no-global-module-test.js

@@ -38,7 +38,8 @@ module.exports = {
                 /* istanbul ignore next: deprecated code paths only followed by old eslint versions */
                 const scope = sourceCode.getScope
                     ? sourceCode.getScope(node)
-                    : context.getScope();
+                    : // @ts-expect-error -- removed in ESLint 10, but needed for ESLint 8 compat
+                      context.getScope();
 
                 const tracker = new ReferenceTracker(scope);
                 const traceMap = {

lib/rules/no-global-stop-start.js

@@ -40,7 +40,8 @@ module.exports = {
                 /* istanbul ignore next: deprecated code paths only followed by old eslint versions */
                 const scope = sourceCode.getScope
                     ? sourceCode.getScope(node)
-                    : context.getScope();
+                    : // @ts-expect-error -- removed in ESLint 10, but needed for ESLint 8 compat
+                      context.getScope();
 
                 const tracker = new ReferenceTracker(scope);
                 const traceMap = {

lib/rules/no-hooks-from-ancestor-modules.js

@@ -47,7 +47,7 @@ module.exports = {
          * @returns {boolean}
          */
         function isInModuleCallbackBody(callExpressionNode) {
-            return (
+            return !!(
                 callExpressionNode &&
                 callExpressionNode.parent &&
                 callExpressionNode.parent.type === "ExpressionStatement" &&

lib/utils.js

@@ -221,7 +221,7 @@ exports.isModule = function (calleeNode) {
  * @returns {boolean}
  */
 exports.isInModule = function (propertyNode) {
-    return (
+    return !!(
         propertyNode &&
         propertyNode.parent && // ObjectExpression
         propertyNode.parent.parent && // CallExpression?